p«™— -™-^ 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY.— Bulletin No. 38. 

A. D. MELVIN, Chief of Bureau. 



TUBERCULOSIS 



OF THE 



IFOOD-PRODUCING ANIMALS 



BY 



D. E. SALMON, D. V. M. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

19 6. 



'^G0^. 



ttpflOglMlBt) 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY.— Bulletin No. 38. 

A. D. MELVIN, Chief oh Bureau. 



TUBERCULOSIS 






OF THE 



FOOD-PRODUCING ANIMALS. 



V 



RY 



D.^ E. SALMON. D. V. M. 




WASHINGTON: 
GOVERNMENT PRINTING OFFICE. 

1906. 



SF 



5\G 



S 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 

Bureau of Animal Industry, 
Wa.s/imrjfon, D. C, May 31, 1906. 

Sir: I have the honor to transmit herewith a paper on Tuberculosis 
of the Food-Producing Animals, by L^r. D. E. Salmon, late Chief of 
this Bureau, who was especiall.y engaged by you to prepare the same. 
I recommend the publication of the paper as Bulletin No. 38 of this 
Bureau. 

Animal tuberculosis, though not nearly so prevalent in the United 
States as in most European countries, is nevertheless a serious prob- 
leu] and a menace to our live-stock industry, and is also regarded as a 
distuK't source of danger to human health. Its infectious nature and 
the means for its repression should be fully understood, and earnest 
and intelligent etforts should be made with a view to its ultimate erad- 
ication from this country. 

The bulletin treats the subject in a very comprehensive manner and 
reviews some of the more important experimental work which has 
served to establish the facts and conclusions presented. The author 
is a recognized authority on the subject with which he deals, and the 
bulletin is written in the light of the latest scientific knowledge. The 
discussion of two phases of the tuberculosis problem which have 
received particular attention in recent years — the relation between tbe 
human and Ixnino forms of tuberculosis and the protection of cattle 
against tul^erculosis hy immunization — should be of especial interest 
at this time. 

Respectfully, A. D. Melvin, 



Hon. James Wilson, 

^Secretary of Agriculture. 



Chief of Bu7'ea n . 



OCl 30 



0. ofo: 



lyos 



CONTENTS. 



Page. 

K 

Introduction ^ 

Part T.— Material facts concerning tuV)erciilosis ^ 

The prevalence of tuberculosis ' 

Extent of the disease in the United States ' 

]\Ieat-inspection statistics - " 

Conditions shown by tests of herds 8 

Relations of contagion and environment to spread of the disease 10 

Tuberculosis in British herds 1 1 

Conditions on the continent of Europe . 1'^ 

The losses from tubercnlosis I"! 

The nature of tuberculosis ^^ 

Effects upon the organs of the body 16 

Symptoms "^ 

Effects npon a herd of cattle 28 

An experiment with tuberculous cattk' - 23 

Spread of tuberculosis by dispersion sale 25 

Histories of affected herds 26 

The cause of tuberculosis 2 / 

The tubercle bacillus 27 

Manner of infection and development of the disease 29 

Infectiveness of milk of tuberculous cows 81 

Spread of tuberculosis from diseased to healthy cattle 87 

The effect of insanitary conditions >^S 

The detection of tuberculosis "11 

Physical examination - "ll 

The tuberculin test -1*5 

Examination of the carcass 52 

Immunization of cattle against tuberculosis - 53 

Early experiments 54 

McFadyean's experiments 56 

Work of Pearson and Gilliland 58 

Von Behring's investigations 60 

Experiments by Hutyra 63 

Thomassen' s experiments 64 

Kliramer's investigations - 66 

Work of Koch and others '^" 

Vallee's experiments 69 

Conclusions regarding immunizatio n 71 

The curative effect of treatment with tuberculin and with attenuated 

tubercle bacilli '^1 

Animal tuberculosis and the public health 78 

Early views ''•'> 

Identity of human and bovine tuberculosis questioned 74 

Investigations by the German commission 75 

Investigations by the German Imperial health otlice 76 

Conclusions now generally held by scientists "8 

3 



4 ILLUSTKATIONri. 

Vage. 

Part II. — The repression of tuberculosis 79 

Measures that may be adopted by individuals 79 

Prevention by avoiding known causes of tuberculosis 79 

Eradication of tuberculosis from the farm 81 

The Bang method of eradicating tuberculosis 82 

A modification of the Bang method 83 

Successful treatment of a Wisconsin herd 84 

Eradication from a Connecticut herd 85 

Recommendations of Regner, of Sweden 86 

Immunization in connection with the Bang method 87 

Destruction of reacting animals and creation of a sound herd 89 

State aid for the eradication of tuberculosis 91 

Federal cooperation for the eradication of tuberculosis 94 

Bibliography 97 



LLUSTRATIONS. 



Page. 

Plate I. Lungs of a healthy hog 16 

II. Tuberculous lungs of hog 16 

III. Portions of tuberculous lungs from cattle 16 

IV. Fig. 1. — Tuberculous spleen of hog. Fig. 2. — Spleen of healthy hog. 

V. Tuberculous liver of cow 20 

VI. Tuberculous pericarditis of cow 20 

VII. Fig. 1.— Tuberculous intestine of a child. Fig. 2. — Tuberculous 

ovary of cow 20 

VIII. Tuberculous udder of cow 20 

IX. Tuberculous lymphatic gland of cow 20 



TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 



INTRODUCTION. 

There are few if any subjects connected with animal husbandry 
upon which more has been written and published within recent years 
than tuberculosis. It has been discussed in the publications of the 
Bureau of Animal Industr}^, in the bulletins of many experiment 
stations, in the reports of live-stock sanitar}^ boards and State veteri- 
narians, and in the columns of the agricultural press. The scientific 
investigations in relation to it have been extremel}" numerous and 
important in their results. Notwithstanding this activit}' in the dis- 
cussion and investigation of the disease, however, there is probably 
no subject upon which there is a greater diticrence of opinion among 
the owners of live stock, and none of which the importance is so 
inadequately appreciated. 

It is unfortunate that in the tirst attempts to control this disease in 
the United States measures were adopted by some of the State authori- 
ties which were so radical and harsh that they aroused the antagonism 
of the cattle owners, the men who above all others should have been 
aided and benefited, and that a spirit was developed in the contests 
that followed which has made it extremely difficult to obtain a dispas- 
sionate and impartial consideration of the measures that are required 
to reheve our farmers from the losses which they are now suffering 
because of the existence of this disease and to remove the danger of 
the far greater losses with which they are menaced. A disease so 
widespread can not be controlled unless those most interested in the 
live stock of the country give their active support to the undertaking. 
It is therefore wise to examine the subject in an unbiased manner, to 
study carefully the nature of the disease, to learn as nearly as possi- 
ble what the losses are, to what extent these losses are liable to increase, 
and whether measures of repression are or are not advisable. It is 
not a question of sentiment, but one of fact, and it should be exam- 
ined as a business proposition. 

The object of this bulletin is to present the facts in as clear and con- 
cise a manner as possible, giving the observations and views of the 
best authorities, and of those who have studied the problem longest 
and are most competent to express an opinion. These facts should be 
known and considered, and if it appears that the prosperity of the 
live-stock industry is threatened, or that serious losses are occurring, 
appropriate action may be taken to check the losses and to remove 

their cause. 

5 



b TTTBERCIJLOSIS OF THE B'OOD-PRODrjCING ANIMAL^^. 

Although tuberculo.sis is an extreuiel\' insidious disease, which may 
enter the herd by an unsuspected channel and develop to alarniintr 
proportions )jef ore its presence is suspected, it is nevertheless a pi"e- 
ventable disease and one the control of which may now be undertaken 
with every prospect of success. But to control or eradicate tubercu- 
losis it is necessary to have a clear comprehension of the peculiarities 
of the disease, of its cause, of its nature, of its mode of extension, of 
its detection. It is one of the problems which could not be handled 
without the aid of science; l)ut now that science has come to the relief 
of the owner of live stock and has shown him how this plague may be 
managed successfully, he is in a position to avail himself of this 
knowledge and to adopt such measures as may be required both to 
stop the losses which it is now causing and to guard against its reap- 
pearance in the future. 

It is dithcult to imagine an3'thing more discouraging or disastrous 
to the plans of the young breeder than to discover that in ))ringing 
together the foundation elements of his herd he has introduced the 
infection of this disease, which counteracts his eli'orts to ])uild up 
a great herd and graduallj" exhausts his capital. Nor is the case 
an)' the less serious when the infection is introduced into a herd 
already established and develoi)ed by the labor and the study of the 
best years of the breeder's life. How many l)reeders have been 
rendered penniless ])y the ravages of the tubercidosis bacillus; how 
many priceless animals have been destroyed by it; how many precious 
strains of blood has it weakened or annihilated! 

And iinally there is the influence of the tuberculous herd upon the 
community. A herd of animals is not bred simply for the entertain- 
ment and use of the ])reeder, but the primary object is to produce and 
sell dairy })roducts, mc^at, and breeding animals to other people. Is it 
right to sell a tuberculous animal to go into another breeder's herd when 
the disease is likely to be carried b}' that animal, to spread, and to dam- 
age or destroy that herd? Is it right to sell tul)erculous cattle or hogs 
for slaughter when we know that many of these animals are slaughtered 
in establishments where there is no inspection and that the diseased car- 
casses may consequently be used for human food? Is it right to sell the 
milk from tuberculous herds knowing that it ma}' be used for the nour- 
ishment of the most delicate children, when such milk frequently if not 
generally contains the tuberculosis bacillus which finds its way to it 
both through the udder of the diseased cow and the dust of the stable? 

These questions, serious from both a moral and a financial point of 
view, confront the breeder of the present day. There can be no 
question that the great body of Ijreeders desire to do what is right, 
and it would appear, therefore, that when a practicable plan of han- 
dling tuberculosis is demonsti'ated to them they will not hesitate in 
adopting it, but will rapidly suppress this disease and eradicate it 
from their herds. 



PART I.— MATERIAL FACTS CONCERNING TUBERCULOSIS. 



THE PREVALENCE OF TUBERCULOSIS. 



EXTENT OF THE DISEASE IN THE UNITED STATES. 

Tuberculosis is the most serious disease of animals with which the 
American farmer is confronted. It is the most prevalent disease of 
cattle, and is becoming very common with swine. It exists in all parts 
of the United States, even in the Rock}" Mountain region, but is most 
frequently seen in dairy cattle and in hogs that have been raised in 
dairy districts. Unfortunately it has also been allowed to propagate 
itself extensively in some of the most valuable beef Ijreeds, as, for 
example, the Shorthorn and the Angus, and its frequency in other 
varieties of cattle appears to be increasing. 

MEAT-INSPECTION STATISTICS. 

The statistics of tuberculosis in this country are fragmentary, and 
give but an imperfect idea of the actual condition, though we have 
sufficient to show that it is not as prevalent as in some of the countries 
of Europe. In the meat-inspection service of the Bureau of Animal 
Industry the number and percentage of carcasses condemned during 
the last five years is shown in the following table. 

Number of carcasses of cattle and hogs inspected and the number condemned for tubercu- 
losis during the years 1901-1905. 





Cattle. 


Hogs. 


Year. 


Number of 
carcasses 
Inspected. 


Number 
of car- 
casses 
con- 
demned. 


Per cent 
of car- 
casses 
con- 
demned. 


Number of 
carcasses 
inspected. 


Number 
of car- 
casses 
con- 
demned. 


Per cent 
of car- 
casses 
con- 
demned. 


1901 


5, 219, 149 
5, 559, 969 
6,134,410 
6,350,011 
6, 096, 697 


6,454 
7,944 
8,598 
10,173 
10,956 


0.10 
.14 
.14 
.16 
.18 


24, 642, 753 
25,277,107 
21,793,728 
24, 128, 462 
25,323,984 


8,660 
14, 927 
20, 299 
34, 656 
64, 919 


0.035 


]90'2 . ... 


.059 


1903 


.092 


1904 . . . 


.143 


1905 


.256 







This table does not show the total number of animals afi^ected with 
tuberculosis, for in many cases only a part of the carcass was con- 
demned, and probably in a still larger numbc^i'of cases the disease had 
progressed so slightly that the entire carcass was passed as fit for 
human food. These milder cases of disease are not included, as cor- 
rect statistics of them are not available. 

7 



» TUBERCULOSIS OF THE FOOD-PEODUCINU ANIMALS. 

TubcrciiloHis in wheep is a rare disease, and in most cases appears to 
be the result of infection from bovine sources. Tliere were but 27 
carcasses of sheep condemned by inspectors of the Bureau of Animal 
Industry on account of tuberculosis during the liscal year 1905, out 
of 7,872,071 animals inspected at the time of slauo-hter. The nodular 
disease of the intestines (caused b}^ the \)aYiisite (Ehi()j)h//(/osto7jm)n colu /)/ - 
hianain) and caseous lymphadenitis are far more frequent and are 
ofttMi mistaken for tuberculosis by persons not thoroughly familiar 
with the distinctive characteristics of these diseases. 

CONDITIONS SnOWN BY TESTS OF IIEKDS. 

\\\ 1901 Doctors Russell and Hastings, of the Wisconsin Agricul- 
tural Experiment Station, published a review of the tests of cattle 
with tuberculin which had been made in the United States, and from this 
review the following summary has been made, which is valuable on 
account of showing the wide distribution of tuberculosis rather than 
indicating the proportion of cattle affected in the respective States.^ ^ 

BesuUs of Ihe tuherrulin tests of cattle in various Slates. 



Vermont 

Massachusetts 

Massaehnsetts, entire herds 

Ci)iiin'cticiit 

New York, 1894 

New York, 1897-98 

Pennsylvania 

New Jersey 



Illinois, 1897-98. 

Illinois, 1899 

Michigan 

Minnesota 

Iowa 



Wisconsin: 

Experiment station tests— 

Susperted herds 

Nonsusjieeted herds 

State veterinarian's tests— 

Suspecteil herds 

Tests of local veterinarians under State veterinarian on cattle 
intended for shipment to States requiring tuberculin certificate . 



Number 
tested. 



60, 000 
21, 685 

4,093 

6,300 
947 

1,200 
34, 000 

2,500 
929 

3,655 



3, 430 

873 



323 
935 



3,421 



Number 
tubercu- 
lous. 



2,390 

12, 443 

1,080 



66 

163 

4,800 



560 



115 
84 



191 
76 



Per cent 
tubercu- 
lous. 



3.9 
50.0 
26.4 
14.2 

6.9 
18.4 
14.1 
21.4 
12.0 
15.3 
13.0 
11.1 
13.8 



35.6 
9.0 



32.5 
2.2 



The State veterinarian of Pennsylvania, Dr. Leonard Pearson, 
thinks that not over 2 per cent of the cattle of that State are tubercu- 
lous; and prol)ably if a general test of all the cattle of the other States 
mentioned were made we should tind a very much smaller proportion 
tuberculous than is indicated by the al)Ove tabuhxr statement. The 
explanation of the high percentages that have been given is found in 
the fact that it has been, for the most part, suspected herds which 
have been tested. Admitting that the greater part of these percent- 
ages are too high, they nevertheless reveal a very serious condition. 

In a report on Tubercivlosis of Cattle, Pearson and RaveneP say 
that it has ])een found by testing herds that the percentage of tuber- 



« The figure references are to bibliography at end of bulletin. 



MATERIAL FACTS CONCP]RNING TTTRERCULOSTR. 



9 



culosis varies from to 100 \)cv ceut, and there urc instances of many 
large herds in which nearly all of the animals have been infected. As 
examples of such herds found in Penns3dvania the following ar^ cited: 



Herd. 


Number 
of cattle 
in herd. 


Number 
of tuber- 
culous 
cattle. 


Per cent 
of cattle 

found 
tubercu- 
lous. 


Herd. 


Number 
of cattle 
in herd. 


Number 
of tuber- 
culous 
cattle. 


Per cent 
of cattle 

found 
tubercu- 
lous. 


I 


174 


166 
59 
17 
14 
37 
37 
20 


95.4 
80.8 
77.3 

100.0 
58.7 
55.2 

100.0 


8 


61 
18 
13 

15 
59 


45 
16 
10 
10 

58 


73.8 


•> 


73 
22 
14 


9 


88.8 


3 

4 


10 


76.9 


11 

12 


66.6 


,5 


63 
67 
20 


89.8 




Total 




7 . ... 


599 


484 


80.8 









These figures of course represent extreme and exceptional conditions. 
Of all the tuberculous herds tested w4th tul)erculin under the auspices 
of the State live stock sanitary board, about 13 per cent of the animals 
have proven to be afflicted with tuberculosis. 

Russell ^ says this disease is the most devastating animal plague with 
which Wisconsin farmers have to contend. Of the 70 herds examined 
by the State live stock sanitary board for the years 1903 and 1904, 49 
were found affected. Very frequently only a small number of react- 
ing animals were found, but the appended list shows some startling 
cases of widespread infection. 

Instances of widesj)read infection of herds that have been tested in Wisconsin during 

1903-4. 



Date of examina- 
tion. 


Number 
of ani- 
mals in 
herd. 


Number 
found 

tubercu- 
lous. 


Per cent 
affected. 


Date of examina- 
tion. 


Number 
of ani- 
mals in 
herd. 


Number 

found 
tubercu- 
lous. 


Per cent 
affected. 


December 16, 1902.. 

April 6, 1903 

May 5,1903 


16 
39 
33 
36 
28 
121 
66 
49 
55 
26 
30 
30 


12 
27 
20 
20 
16 
24 
25 
24 
27 
15 
23 
23 


75 
69 
60 
55 
57 
20 
44 
49 
49 
67 
76 
76 


January 5, 1905 

January 25, 1905 . . . 
February 5, 1905... 
February 12, 1905.. 

March 20, 1905 

April 20, 1905 

April 25, 1905 

May 3, 1905 

May 8, 1905 

Total 


27 
38 
14 
60 
20 
22 
30 
31 
92 


21 
23 
12 
14 
13 
20 
17 
21 
31 


77 
60 

85 


May 11, 1903 

June 2, 1903 

June 3, 1903 

October 22, 1903 

December 9, 1903... 

March 21, 1904 

March 31, 1904 

April 17,1904 

October 26, 1904.... 


23 
65 
91 
57 
69 
33 


853 


428 


50 



If such widespread infection as these examinations indicate were 
found in all herds the stock interests of the countr}' would be on the 
verge of bankruptcy, and yet the record above presented does not 
give by any means all of the cases. 

A brief list of infected herds which have been more or less carefully 
studied is useful in showing the extent to which the disease develops 
under the best conditions of sanitation, and in indicating' the difficulty 
of building up a herd of good cattle even under skillful supervision 
unless the health fulness of the herds from which the purchases are 
made has been ascertained. 



10 



TUBERCULOSIS OF THE FOOD-PKODUCING ANIMALS. 



Herd of- 



Maine Stale Agricultural College (1886) * 

Soldiers' Home, Washington, D. C/-> 

Government Hospital for the Insane, Washington, D. C' 

Massachusetts Agricultural College ^ 

New Jersey Agricultural Experiment Station » 

Kansas Agricultural College '■' 

Wisconsin Agricultural l-^xperiment Station '" 

Connecticut Agricultural College, Storrs Experiment Station 'i . 

Colorado Agricultural ('oHrKo '- 

Vermont Agricultural Kxpcriment Station 

Ohio Agricultural Experinicut Station, first test i-* 

Texas Agricultural Exiicrimcnt Station 

Louisiana Agricultural Exiicrinient Station n 

New Hampshire Ccillcgc of Agriculture and the Mechanic Arts' 

New York (Geneva ) Agricultural Experiment Station ^'> 

Utah Agricultural Ex]icriment Station i' 

New Mexico Agricultural Experiment Station is 

Central Experimental Farm, Ottawa, Canada i'-' 



Number 
in herd. 



51 
63 
102 
32 
42 
56 
30 
49 
31 
33 
30 
21 
22 
55 
27 
18 
19 
38 



Number Per cent 
tubercu- tubercu- 
lous, lous. 



100.0 
84.1 
77.0 
78.1 
59.5 
26.8 
86.6 
38.8 
32.2 
63.6 
46.6 
47.6 
31.8 
18.2 
55.5 
72.2 
15.8 
55.3 



RELATIONS OF CONTAGION AND ENVIRONMENT TO SPREAD OF THE 

DISEASE. 

While bad sanitary conditions undoubtedly favor the spread of 
tuberculosis it is not preeminent!}' a disease of poor, neglected, under- 
fed scrul) cattle, for the better class of cattle have suffered from it to 
an even greater degree. It has been constantly imported with pure- 
bred stock, and has consequently been introduced into the best herds 
and has extended from these to the daiiy herds and common cattle. 

The beef cattle coming to our markets are still remarkaljly free from 
tuberculosis, but the disease appears to be increasing among this class 
of animals, as is indicated by the percentage of condemnations in the 
meat-inspection service. There appears to be no climate and no 
method of handling cattle which entirely arrests the spread of the 
disease. This is shown by its existence upon the ranges of our 
Western States, and to an even greater extent in the herds of 
Argentina, Australia, and New Zealand. Considering that these 
cattle live in the open air and in climates that have been considered 
remarkably favorable for people affected with tuberculosis, >ve can 
not l)ut be impressed with the importance of avoiding the use of 
tubercular breeding stock and thus guarding against the dissemination 
of this contagion. 

There are some portions of the world — as, for example, the northern 
parts of Norw ay and Sweden, the steppes of Russia, Iceland, and parts 
of Africa and South America — where tuberculosis is said to l>e quite 
rare. The cattle of the Island of Jersey appear to be free from it. 
This seems to have been true of the common or native cattle of many 
countries. In the United States there are numerous sections where 
the original stock of cattle has been bred without much admixture 
with the improved breeds and where few outside cattle have been 
introduced. These sections are generally free from tuberculosis. It 
has also been observed in Argentina and other countries that this dis- 
ease is unknown among the native cattle, but that it has been intro- 



MATERIAL FACTS CONCERNTNa TITBEROULOSIS. 11 

duced with the improved breeds from Europe, and is now common 
with both purebreds and grades. It is even held by Professor Bang- 
that tuberculosis was brought to Denmark in the first half of the nine- 
teenth century l)y cattle from Switzerland, Schleswig, and England, 
and that this method of distribution may now be seen in Sweden and 
Norway, particularly through the introduction of English cattle. 

These facts contirm the conclusions from scientific observation and 
experimentation that tul^erculosis develops only by infection from 
some existing case of the disease; and that it will be possible in the 
future, as it has been in the past, for a section or a State to raise cat- 
tle that are free from it. 

TUBERCULOSIS IN BRITISH HERDS. 

The British herds appear to be justly chargeal)le with much of the 
tuberculosis of cattle and swine which now exists in many parts of the 
world. The unparalleled skill of the British breeders in developing 
useful and superior breeds of animals, and particularly of beef cattle, 
long since attracted the attention of the world and led to the difl'usion 
of this improved blood through the herds of many countries. But, 
unfortunately, the breeders of Great Britain were not as skillful in 
avoiding tuberculosis as they were in increasing the size, perfecting 
the form, and hastening the maturity of the animals, and the result 
has been not only that they unwittingly propagated the disease, but 
that they distributed it in the most extensive manner. 

It would not be correct to assume, however, as some have been 
inclined to do, that Great Britain is the source from which has been 
derived the tuberculous infection of all other lands, for the equal or 
greater prevalence of the disease in some other countries, notabl}' in 
Germany, France, Holland, and Belgium, indicates an infection not less 
remote. It is probably true that there were infected localities in all 
these countries, and that, with the improvement of the means of com- 
munication and the development of commerce, the exchange of cattle 
became more frequent, so that the infection, which had previously 
been limited to a few small districts, was everywhere distributed. At 
that time the nature of the disease was not well understood, and for 
many years its existence in the larger part of the ati'ected animals was 
not even suspected. It was therefore quite natural, when the advance- 
ment of scientific knowledge made it possible to detect tuberculosis 
readily, and when the disease was found to affect a large proportion of 
the cattle, to charge imported cattle with its introduction. 

Nevertheless there are many cases in which the introduction of 
tuberculosis may ])e clearly traced to British cattle, and among these 
may be cited the herds of Canada, of the United States, of Argentina, 
of South Africa, of Australia, and of New Zealand. That the herds 
of England and Scotland are badly infected there is ample proof. 



12 



TUBERCULOSIS OF THE FOOD-PRODUCTNO ANIMALS. 



The testing of the Queen'.s herd at Windsor some years ago, and tlie 
unexpected discovery that 36 out of 40, or 90 per cent, were affected 
and that some of them were in a very advanced stage of disease aroused 
public interest in the subject and brought out much information. The 
returns from testing cattle w^ith the tuberculin supplied by the Royal 
Veterinary College, as stated in March, 1900, showed that among 
15,392 animals tested 1,105, or 26 per cent, reacted. Taking the vari- 
ous tests made of which records are at hand there is an aggregate of 
20,930 head examined, of which 5,111, or 26 per cent, were pronounced 
tubercular. 

That some of the best purebred herds of Great Britain are badly 
infected is known by the results of testing with tuberculin cattle from 
such herds in the quarantine stations on this side of the Atlantic, and 
also by testing cattle which were desired for shipment to the United 
States. The following table shows the number of cattle tested b}" the 
United States inspector stationed in Great Britain and the number 
that were rejected: 



Year. 


Number 

of cattle 

tested. 


Number 
rejected. 


1901 


161 

1,067 

631 

239 

23 


18 


1902 


139 


1903 


98 


1904 


«7 


1905 


11 








Total . . 


2,131 


303 







Of the purebred cattle which were to be imported into the United 
States during the years from 1901 to 1905, inclusive, 11.2 per cent 
reacted; but this is not a true indication of the proportion of animals 
in these herds affected with tuberculosis, since only those animals w^ere 
offered which were supposed to be in condition to pass the test suc- 
cessfully. It must also be admitted that the more or less frequent 
testing of the animals in these herds has reduced the proportion of 
animals which react. The percentage of tubercular animals in these 
herds is, therefore, without doubt considerabl}^ greater than the per- 
centage of reactions obtained b}^ the inspector. 

The proportion of reactions to tuberculin obtained with different 
breeds of animals is interesting as indicating to some extent the rela- 
tive infection of the different breeds; although, owing to the compar- 
atively small number of animals covered by the tests, conclusions from 
these tigures should not be too absolute. The following table shows 
the number of animals of each of the principal breeds tested and the 
number and percentage which reacted: 



MATERIAL FACTS CONCERNINa TUHEKOULOSIS. 



13 



Breed. 



Ayrshire 

Aberdeen- Angus 

Shorthorn 

Jersey 

Galloway 

Hereford 



Number 
of ani- 
mals 
tested. 



52 
390 
248 
366 
114 
417 



Number 
of ani- 
mals 
which 

reacted. 



16 
108 
60 
24 
6 
17 



Per cent 
of ani- 
mals 
which 
reacted. 



30.7 

27.7 

24.2 

6.8 

5. 2 

4.1 



CONDITIONS ON THE CONTINENT OF EUKOPE. 

The frequency of tuberculosis among domesticated animals on the 
continent of Europe is generally admitted. The statistics which reach 
us from there are somewhat fragmentary, but sufficient to demonstrate 
the gravity of the situation. 

In France Professor Nocard estimated that in the regions of Brie 
and Beauce approximately 25 per cent of the cattle were tubercular, 
while the cattle of Auvergne and Limousin (exporting districts) were 
free from the disease. In Brittany, Nivernais, Upper Vosges, in the 
southeast, and in certain valleys of the Pyrenees, the disease affects 
from 25 to 50 per cent of the cattle. 

In Holland the percentage of tuberculous cattle found among those 
slaughtered in Amsterdam gradually increased from 1.7 per cent in 
1888 to 13 per cent in 1898, while the proportion of swine affected 
increased from 1A7 per cent in 1895 to 3.58 per cent in 1898. 

The percentages of tubercular cattle found in the slaughterhouses of 
Prussia and Saxony are shown by the following table: 



Year. 


Prussia. 


Saxony. 


1895 




11.4 
15.8 
14.4 
16.4 


97 og 


1897 




1399 


29 76 


1902 


30 98 







In some of the cities the percentage has been even greater; for ex- 
ample, Berlin, 1902, 25.35 per cent; Breslau, 1902, 31.67 per cent; 
Leipsic, 1902, 36.16 per cent; Zwickau, 1902, 36.27 per cent; Zittau, 
1902, 41.24 per cent.'" 

In Sweden, according to Kegner,'^ there were tested, during the 
years 1897-1904, 226,864 head of cattle, of which 69,717, or 30.7 per 
cent, reacted. 

In Norway, Bang"^' states that according to Malm there had been 
tested, up to the beginning of 1902, 131,995 cattle, of which 8,029, or 
6.1 per cent, reacted. In Finland, during the years 1894-1900, 75,447 
cattle were tested, the proportion of reactions being 13.7 per cent, and 
according to the official statistics 21,994 were tested in 1903 and 5.6 
per cent reacted. 



14 



TrHKRCULOSlS OF THE FO()D-PR()DUCIN(} ANIMALS. 



Ill Denmark the re.sults of the tuberculin tests and of the efforts to 
control the disease have been extremely interestino-. Bang"' has 
i-ecentl}' reported the complete statistics of this work in that country, 
as follows: 

i\V,SN.//.s' ';/' liil'iTciilin /('n/.s of cattle in DeiDimrk fvuni 18US to 1!)04. 



Period. 



April, 1893, to June, 1894. . . 
June, 1894, to October, 1895 
October, 1895, to May, 189G 
May, 1896, to June, 1897 ... 
June, 1897, to May, 1898. . . . 
May, 1898, to January, 1899 

Year 1899 

Year 1900 

Year 1901 

Year 1902 

Year 1903 

Year 1904 

Total 



Farms. 



}'• 



327 
,873 
930 



17, 268 10, 621 



First 

testing. 



327 

1 , 645 

749 

3, 012 

2, 165 

618 

543 

417 

259 

396 

213 

277 



Number 
of ani- 
mals 
tested. 



8,401 
44, 902 
20, 791 
84, 897 
65, 788 
35, 533 
33, 568 
26, 078 
18, 818 
23, 347 
19, 364 
23, 164 



404,651 



Number 
of ani- 
mals re- 
acting. 



3,362 
17,303 
6,622 
21,668 
15, 642 
7, 725 
6,759 
4,976 
2, 857 
3, 531 
2, 875 
3, 750 



97, 070 



Per cent 
of tested 
animals 
reacting. 



40.0 
38. 5 
31.9 
25. 5 
23.8 
21.7 
20.1 
18.0 
15.2 
15.1 
14.8 
16.2 



24.0 



The proportion of tuberculous swine found in the slauohterhouses of 
some of the German cities is interestino- as showing the extent to which 
the disease ma}^ develop among this class of animals. The statistics 
with reference to these findings are presented below: 



Berlin 

Do 

Do 

Danzig 

Do 

Magdeburg 

Do .... . 





Per cent 


Year. 


of tuber- 
culous 




swme. 


1895 


3.09 


1899 


4.01 


1902 


5.40 


1898 


5.66 


1902 


5.49 


1896 


1.91 


1898 


3.55 



City. 



Magdeburg 
Potsdam . . . 

Zittau 

Zwickau . . . 

do 

do 



1902 
1900 
1902 
1896 
1899 
1902 



Per cent 
of tuber- 
culous 
swine. 

5.19 

7. .55 
5. 35 
6.06 
3.89 
3.41 



It is plain that tuberculosis is far less frequent in the United States, 
with lioth cattle and hogs, than it is in Europe; but it also appears 
from the rate of increase shown by the statistics of various parts of the 
world, including our own meat-inspection reports, that unless its dis- 
semination is by some means checked it will require but a few years 
for it to gain the same headway here that it has acquired there. 

THE LOSSES FROM TUBERCULOSIS. 

It is a ditticult matter to estimate with any approach to accurac}^ the 
losses from a disease like tuberculosis, concerning which the statistics 
are incomplete in every respect. There are now, however, approxi- 
mately 11,000 carcasses of beef and 65,000 carcasses of hogs condemned 
each year by the Federal meat inspectors on account of tuberculosis. 
We should not be far wrong in estimating the loss on these carcasses 
at present prices as $40 each on the beef and $12 each on the pork. 



MATERIAL FACTS C0NCP:RNING TUBERCULOSIS. 15 

We should therefore have as the net annual loss from the condemna- 
tion of carcasses $440, 000 for beef and $780,000 for pork, or a total 
of $1,220,000. This statement, however, does not include the 617 
parts of ]>eef carcasses and the 112,105 parts of hoo- carcasses which it 
was necessary last year to condemn for the same cause, and the approxi- 
mate value of which can not be ascertained. 

In addition to the carcasses condenmcd l)v the Federal inspectors, 
there are a considerable number condemned ))y State and nmnicipal 
inspectors. These are mostly carcasses of dairy cattle killed in the 
work of suppressing- tuberculosis, or of cows no longer profitable in 
the dairy which are sent for slaughter to the smaller abattoirs. The 
aggregate number of these has not been ascertained, but in some years 
it has amounted to several thousand carcasses. 

The losses to the dairy industr}^ from tuberculosis have been enor- 
mous from decrease in milk and depreciation and death of animals. 
The dairy herds have been affected to a greater extent than any others, 
and the infection has as a rule spread through the cows of a herd 
until 50 to 80 per cent of the animals were affected. In the early 
stages of the disease the product of the cows is not visibly lessened, 
but as the tubercular process develops the animals often become 
feverish, their milk is diminished in quantity, and they lose flesh and 
are no longer profitable. The losses from shrinkage of the milk and 
from the destruction of so many cows must be tremendous, but it has 
never been definitely determined. 

An extremel}^ serious phase of this subject is the effect of the dis- 
ease in destroying valuable families of cattle and blood lines which 
can never be renewed. In most of the breeds there are certain families 
or strains of blood which have been developed by long and skillful 
selection and which represent the one marked success in a breeder's 
life. The representative animals of such a strain are generality few in 
number and may all be in one herd. Under such circumstances the 
introduction of tuberculosis has often meant the annihilation of the 
strain and the blotting out of the achievements of a lifetime of toil 
and study. Such losses can scarcely be measured in dollars and cents, 
but the}' are no less real and no less serious as an obstacle to the 
development of the cattle industry. 

The losses to the breeders of purebred beef cattle have also l)een 
and still are so great as to merit the most serious consideration. When 
the individual animals of a herd are worth hundreds or even thousands 
of dollars, the introduction of a fatal infectious disease may soon 
cause the loss of a fortune, and this is just what has occurred upon 
many a breeding farm. Such a danger, always present and always 
menacing an industry, nmst discourage individual eft'orts and do much 
to prevent the attainment of lasting prosperity. 

The influence upon our export trade of regulations relative to 



16 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS, 

tuberculosis will probabl}^ ))eeome more and more unfavorable. 
Breeding- and dairy cattle for Canada and Argentina nuist now be 
tested and found free from the disease before they will be admitted. 
The tendency everywhere is to make more stringent regulations, and 
any considera])le increase in the prevalence of the disease would have 
an unfavorable eti'ect upon the sale of live animals, meats, and dairy 
products, even if burdensome regulations were not imposed. To meet 
successfully the increasing competition in the markets of the world it 
is important to have products which it can be shown are produced 
from healthy animals and which do not carr^^ danger of any kind to 
the health of the consumer. 

THE NATURE OF TUBERCULOSIS. 

EFFECTS UPON THE ORGANS OF THE BODY. 

The most striking feature about the disease Itnown as tul)erculosis is 
the formation in different parts of the animal bod}", but particularly in 
the lymphatic glands, the lungs and liver, of small masses or nodules, 
yellowish, gravish, or whitish in color, v/hich are called tubercles. It 
is from this characteristic that the disease receives its name. Tuber- 
culosis is therefore that diseased condition of the animal body in which 
tubercles are formed. There are, however, other diseased conditions 
accompanied l)y the formation of similar nodules which ma}' also be 
called tubercles, and therefore it would be necessary in formulating 
an exact definition of tuberculosis to specify tubercles caused by the 
JBaclUus tuberculosis. We might therefore say that tulierculosis is the 
disease caused by the Bacillus tuhercnlosis and characterized liy the 
formation of tubercles in various parts of the animal body. 

It was formerly believed that the lungs were affected in nearly every 
case of tuberculosis, but more careful studies have shown that the 
glands of the neck and chest are even more frequently affected than 
the lungs. From the very careful autopsies made on the animals 
of the Soldiers' Home, Washington, D. C, in 1893 by Dr. Theobald 
Smith,"^ at that time pathologist of the Bureau of Animal Industry, 
the following interesting information as to the parts affected was 
obtained : 

Total numl )er of animals in the herd 60 

Total number of animals infected (88 per cent) 53 

Numl^er in which retropharyngeal glands only were affected 5 

Number in which the bronchial glands only were affected. 5 

Number in which the mediastinal glands only were affected 5 

Number in which the thoracic glands but not the lungs were diseased 27 

Number in which lungs were affected 20 

Number Avith exclusively thoracic lesions 26 

Number with exclusively abdominal lesions 1 

Total number in which retropharyngeal glands were affected 9 

NumliL'r in wliich disease of the thoracic organs was detected 47 

Number in which lungs were diseased and glands healthy 1 

Number in which digestive tract, int-luding head glands, was affected 26 

Number in which intestinal walls were affected 1 

Nundjer in which mesenteric glands were affected , 16 



Bulletin No. 38, B. A, I. 



Plate I. 




LUNGS OF A HEALTHY HOG. 



Bulletin No. 38, B. A. I, 



Plate II, 




TUBERCULOUS LUNGS OF HOG 



killetin No. 38, B. A, I. 



Plate III. 






PORTIONS OF TUBERCULOUS LUNGS FROM CATTLE 



Bulletin No, 33, B, A, I. 



Plate IV, 




TUBERCULOUS SPLEEN OF HOG. 



SPLEEN OF HEALTHY HOG. 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 



17 



Number in which portal glands were affected 10 

Number in which mesenteric and not jiortal glands were affected 10 

Number in which portal and not mesenteric glands were affected 4 

Number in which parenchyma of liver was involved 2 

Number in which serous membranes were affected 2 

Number in which udder glands were affected 1 

From this statement the following- table showing the location of the 
disease has been calculated in percentages: 



Organs affected. 



Retropharyngeal glands only 

Brimehial glands only 

Mediastinal glands only 

Thoraeic glands but not the lungs 

Lungs 

Lungs but not the thoracic glands 

Thoracic organs only 

Total thoracic organs 

Aljdominal organs only 

Total retropharyngeal glands 



Per cent. 



9.4 
9.4 
9.4 

50.9 
37.7 

1.9 
49.1 
88.7 

1.9 
17.0 



Organs affected. 



Total digestive tract, including head 

glands 

Intestinal walls 

Mesenteric glands 

Portal glands 

Mesenteric and not portal glands 

Portal and not mesenteric glands 

Parenchyma of liver 

Serous menil)ranes 

Glands of udder 



49. 1 

1.9 

30.2 

18.8 

18.8 

7.5 

3.8 

3.8 

1.9 



This table shows the great freciuenc}' with which the tubercular 
lesions are found in the glands. If we add the cases in which the 
thoracic glands ])ut not the lungs were affected (50.9 per cent) to those 
in which the retropharyngeal glands only were affected (O.tt per cent), 
we find that (>( > per cent of the cases had these glands, and not the lungs, 
affected. It is very seldom that the lungs are affected without the 
thoracic glands ])eing also diseased. 

Doctor Pearson " has given the result of 1,200 post-mortem exami- 
nations made under his direction for the State live stock sanitary 
board of Pennsylvania. The following is a ta))ular statement of these 
observations, the organs mentioned l)eing arranged in the order of 
frequency of infection. Practically all of the animals covered by this 
table were milch cows. 

JJistrihuflon of lesioyis hi 1,300 cases of tuherndosis. 



Organs affected. 



Number 
of cases 
in which 
affected. 



Per cent 
of cases 
in which 
affected. 



Mediastinal lymphatic glands 

Right lung 

Left lung 

Bronchial lymphatic glands 

Small intestine 

Mesenteric lymphatic glands 

Pleura 

Liver 

Large intestine „ 

Postpharyngeal lymphatic glands .' 

Peritoneum 

Lymphatic glands of udder , 

Diaphragm 

Portal lymphatic glands 

Lymphatic glands of flank 

Udder 

Pericardiiun 

Lymphatic glands of shoulVler 

Stomach 

Spleen 

Uterus 

Kidneys 



60. 42 

60.33 

57. 08 

33.67 

32.33 

23.17 

22. 00 

20.58 

15. 75 

15. 08 

14.00 

13.42 

11.33 

10. 25 

9.00 

8.67 

8.17 

7.75 

7.17 

5.67 

5. 50 

2. 08 



1881— No. 88—06- 



18 TTTBERCITLOSIS OF THE FOOD-PRODUCING ANIMALS. 

Of course in a great man}' of these cases lesions were found in a 
nuni])or of org'ans, and sometimes they were distributed throughout 
the abdominal and thoracic cavities. No reference is made to lesions 
in the brain, skin, muscles, bones, or joints, because these parts were 
not examined in all cases. 

Wherever the disease is located, it is usually made manifest l)y the 
formation of a number of tubercles the size of a pin head or smaller. 
If the tubercles are numerous and situated near to each other, they 
ma}' become joined together in varying- numbers, forming tubercular 
masses. Both the individual tubercles and the tubercular masses 
undergo certain changes by which they may become soft, cheesy, or 
semiliquid, and in other cases they may become gritty or hard through 
the depositing of lime salts. By such changes a lymphatic gland may 
be greatly enlarged and tilled with tubercular material, which, when 
cut across, is found to be calcified and hard or broken down and soft- 
ened until it has acquired a cheesy or pasty consistency. 

The tubercles which form in the lungs go through changes similar 
to those just described as occurring in the glands, but, owing to the 
different structure of these organs, there are complicating changes in 
the lungs which give the lesions a somewhat different appearance. 
The irritation caused l)y the tubercles usually leads to the development 
of bronchitis with an a])undant catarrhal secretion which fills the 
smaller air tubes, shuts off the air supply, causes the collapse of the 
lung tissue thus deprived of air, and leads to the depositing of yellow- 
ish cheesy matter in the air tubes and cells of this portion of the lung. 
This condition is known as tubercular broncho-pneumonia. 

In Plate I the lungs of a healthy hog are shown in order to enal)le the 
reader to compare these with the illustrations of tuberculous lungs. 
The color is uniform except for light and shade, the surface is smooth, 
and the tissue is spongy and elastic. The normal lungs of other kinds 
of animals have a similar appearance. The tulierculous lungs of a hog 
are represented in Plate II. Innumerable small tu))ercles are seen 
almost covering the surface, and many lobules are collapsed and of a 
deep red color. Toward the upper portion of the illustration, between 
the lungs, the enlarged and tul)erculous bronchial glands may be dis- 
tinguished. These lungs were very severely affected, but the tubercles 
have for the most part remained isolated— that is, they have not united 
and formed the tuliercular masses which are sometimes seen. 

Plate 111 shows different kinds of tubercular lesions observed in the 
lungs of cattle. In the lower figure there are small tubercular masses 
distributed throughout a limited portion of one of the lungs. The 
middle figure shows an aggregation or union of such masses, through 
which process a mass of considerable size has been formed, and around 
the border of this may be distinguished a white fibrous wall which 
when complete enveloped the tubercular material and shut it off' from 



MATERIAL FACTS CONCERNING TTTl?EK(^TTLOSIS. 19 

the tissue of the hmgs. The upper tig-ure represents a tul)erciilar mass 
similar to that just described, hut okler. The fibrous wall surrouudiuo- 
it is more distinct and thicker, while the contents are more broken 
down and homogeneous. 

When a large number of tubercles develop on the surface of the 
lungs, an inflammation of the pleura may l)e caused, with the forma- 
tion of much new tissue and the adhesion of the lungs to the ribs or 
the diaphragm. Sometimes the disease has a peculiar tendency' to the 
development of tubercular growth upon the pleura and other serous 
mem])ranes. The tubercular masses l)ud and l)ranch, thus forming 
large wartlike growths; or groups of nodules may even hang from the 
suvface suspended by delicate threads or fibers giving the appearance 
of a bunch of grapes. These collections of tubercles have often been 
called grapes, and this form of the disease is known as ''pearl}^ dis- 
ease," on account of the pearly color and glistening appearance of the 
serous memln-ane covering the projecting buds and spherical masses. 
In many cases both the lungs and serous membranes are afl'ected, but 
often there are extensive growths of this kind upon the surface of 
the lung, while, singularly enough, the tissue of the lung remains 
unattached. 

With extensive tubercular disease of the lungs and pleura the 
bronchial and mediastinal lymphatic glands generally become loaded 
with tubercular deposit and enormously enlarged. In some instances 
they constitute masses of tubercular material many pounds in weight. 

The organs in the al)dominal cavity are also frequently the seat of 
tubercular disease. In the herd of the Soldiers' Home, above referred 
to, more than 40 per cent of the animals had al)dominal lesions. The 
mesenteric and portal glands are the organs most commonly affected, 
but tubercles arc often found in other lymphatic glands of this region, 
and also in the liver, spleen, kidneys, ovaries, uterus, and even in the 
intestinal walls. 

In Plate IV the figure to the right illustrates the appearance of the 
normal spleen of a hog. Its uniform color and regular outline should 
be noted. The figure to the left represents the tubercidar spleen of 
a hog. Observe here the yellowish masses of tubercular material 
which cause elevations of the surface, and the color of which may be 
plainly distinguished through the membrane which covers the organ. 

Plate V was made from a case of tuberculosis of the liver of a cow. 
A large portion of the lobe of the liver which is shown in the phxte 
has undergone tuberculous changes and been converted into a solid 
mass of tul)ercular material. The nodules seen in this illustration are 
in various stages of the disease, but the majority- contain the yellowish, 
partly chees}', part!}' gritty sul)stance which is characteristic of 
advanced tuberculous degeneration. 

Plate VI is an illustration made from a case of severe tulxu'ciUous 



20 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

pericarditis of a cow. The pericardinin or sac surrounding the heart 
is seen g-reatly thickened b}^ the formation of tubercular material, and 
the heart itself is compressed and misshapen. 

In Plate VII the lower figure represents the tuberculous ovaries of a 
cow. Many nodules of a size approximating that of a pin head are 
visible over the surface of the organ, and some are deeply buried in 
its substance. The upper figure was drawn from a portion of a child's 
intestine which was thickly covered with small tubercles. The great 
development of the tubercular process in this case is readily appre- 
ciated from the appearance of the plate. This class of cases has been 
attributed to infection taken into the stomach, and some of these cases 
are supposed to be due to infected cow's milk. • 

The udder of cows is sometimes attacked b}^ tuberculosis, in which 
case one of the quarters is found to be swollen, uniformly firm or 
hard, and painless. In rare cases one-half of the udder may be 
aft'ected. Tubercles are formed throughout the ajffected part of the 
organ, and there may be tubercles and tuberculous ulcerations upon the 
surface of the mem1)ranes lining the milk tubes. When such a condi- 
tion is established the milk becomes thin and watery and contains innu- 
merable tubercle bacilli. As the disease progresses larger nodules, 
such as have been described in other organs, form within the udder 
and undergo degeneration, softening, and liquefg-ction. If such a 
tuberculous mass opens into a milk duct, as is often the case, the 
liquid or semiliquid contents become mixed with the milk. 

Plate VIII is an illustration of a tuberculous udder which has been cut 
across to show the distribution of the tuberculous material. This part 
of the organ is filled and distended with the tuberculous deposits, and 
the milk cistern showing near the lower portion is ulcerated, lined 
with tubercles, and covered with cheesy particles. At the upper 
portion of the illustration may be seen the supramammary lymphatic 
gland, which is greatly enlarged and studded with small tubercles. 

Tubercles are often found in the lymphatic glands in front of the 
shoulder and in the flank, and in, those embedded in various parts of 
the muscular tissue. As such glands are situated in the portions of 
the carcass used for food, it is important that the}^ should be examined 
before the carcass of a tuberculous animal is utilized for this purpose. 
A tuberculous lymph gland is shown in Plate IX. 

The bones may also be invaded by the tubercular process, especially 
in swine, and sometimes the whole interior of one or more bones will 
be filled witli tul)ercular material, either just developed or undergoing 
degeneration. Often the joints are afi'ected, causing swelling, inflam- 
mation, and lameness. The lirain and spinal cord are by no means 
exempt from tuberculous disease, but owing to the diflicult}" of remov- 
ing these organs for examination we have fewer statistics relative to 
them than to most other parts of the body. Semmer found tubercu- 



Bulletin No, 38, B, A, I. 



Plate V. 




TUBERCULOUS LIVER OF COW. 



Julletin No, 3g, 6, A. I, 



Plate VI, 




TUBERCULOUS PERICARDITIS OF COW. 



Bulletin No. 38, B, A. 



Plate VII 




TUBERCULOUS INTESTINE OF A CHILD, 




TUBERCULOUS OVARY OF COW. 



bulletin No, 38, B, A, 



Plate VIII, 




TUBERCULOUS UDDER OF COW. 



Bulletin No, 38, B. A. 1. 



Plate IX. 



Haines del. 1904. 



X 



..J 




TUBERCULOUS LYMPHATIC GLAND OF COW. 



MATERIAL FACTS CONCERNIN(; TITBEROITLOSTS. 



21 



losi.s of the brain in 4 out of -iU cases examined. The tubercles are 
located on the membranes of the bi'ain and spinal cord, and are also 
found scattered through the interior tissue of these organs. 

It will be seen from what has preceded that tuberculous disease ma}^ 
b(^, found in any part of the animal body, and that while there are 
certain organs which are affected more frequently than others, none 
of the living tissues is altogether exempt from its invasion. 

The generalized form of tuberculosis is that in which the infection 
gets into the blood and is distri])uted through the circulation to man}' 
parts of the bod3^ Slaughterhouse statistics of diti'erent countries of 
Europe indicate that about 9 or 10 per cent of the cases of tul)ercu- 
losis in cattle are in this forni. Kieck, quoted by Ostertag, states, as 
a result of the careful examination of 130 cases of generalized tuber- 
culosis in the abattoirs of Leipzig from 1S80 to 1891, that the follow- 
ing percentages indicate the proportion of these cases in which the 
different organs of the carcasses were affected: 



Organs. 


Per cent. 


Organs. 


Per cent. 




100.0 
83.0 
73.0 
57.4 
52. 5 


Museles and intermnscnlar 


lymph 






49 3 


Intestinal canal 




18 6 


Serous membranes 


Udder 


16 7 


Kidneys 


Bones .... 


S S 









SYMPTOMS. 

In the great majority of cases of tuberculosis in animals the symp- 
toms are slight and not at all clear in theii- indications. As the func- 
tions of the body must be disturl)ed more or less before any symptoms 
are apparent, it is i)lain that in the earliest stages of the disease there 
are no syuiptoms, and that when sj^mptoms develop the disease is 
alread}' considerably advanced. It is onl}?- when the affected part is 
located where it may be easih' examined that s,ymptoms are shown by 
which the infection may be detected at a comparatively early stage. 
Thus when the udder or the glands of the neck are the seat of tuber- 
culosis the existence of the trouble is more likely to be revealed than 
when the affected organ is within one of the bod}' cavities. 

If the larynx, the air tubes, or the lungs are affected there is a short 
cough, which is heard particularly in the morning at feeding time or 
wh(Mi the animal is let out of the stable in the cold air, or after it has 
been di'inking cold water, and especially after violent exertion. This 
cough generally liecomes more prolonged and convulsi\'e as the disease 
advances. 

In case the uterus or ovaries are effected there may be abortion or 
sterilit}^ with al)normal sexual manifestations. If the intestines are 
affected there may be irregular attacks of diarrhea. If a joint is dis- 
eased it is revealed l>y lameness. 

As the disease progresses the general health of the animal and the 



22 TITBEECULOSIS OF THE FOOD-PKODUCING ANIMALS. 

I'unctioiis of nutrition iii'c ati'ecUMl. Animals wliicli have been in good 
tiesh and layino- on fat fail to i)rotit by their food and begin to lose 
flesh; there is a lusterless, staring, rough coat of hair, the skin 
becomes tense, the liones prominent, and the eyes sunken in their 
sockets! The milk secretion diminishes and the milk becomes thin, 
watery, and l)lue. In case the serous meml)ranes of the chest become 
irritated by the tubercular deposits, pressui-e applied over the ribs 
may cause the diseased animal to cough, moan, seek to escape, and 
otherwise manifest eyidence of tenderness in this region. 

The ear applied to the walls of the chest may sometimes detect 
abnormal sounds, such as loud erepitation, gurgling, whistling, and 
creaking, or there may be areas where the respiratory murmur is 
entirely lost. Percussion sometimes shows abnormal resonance and 
sometimes areas of dullness corresponding to tubercular deposits or 
adhesions of the lungs to the chest wall. 

In most animals there is high temperature, progressive emaciation, 
and loss of strength until death results. With some cases the general 
nutrition of the body remains unaffected and these symptoms of the 
Hnal stages of the disease are postponed until after the lungs or other 
vital organs have been almost completely tilled with tubercular deposit. 
But if the disease continues to make progress there must come a time 
when the nutrition and vigor fail to maintain themselves and rapid 
prostration follows. There are cases, however, with animals as with 
men, in which the forces of the body triumph over the disease, and 
the progress of the tubercular formation is arrested. The tubercular 
material is then inclosed by fibrous walls which shut it off' from the 
living tissues of the bod}^, caseation and softening or calcification 
take place, and in the course of time the ])acilli may die and disap- 
pear. Unfortunately, these cases are the exception and not the rule. 

In those cases 'svhich progress to a fatal end the attitude and general 
appearance of cattle are quite characteristic during the final stages. 
The emaciation is extreme; the outlines of the bones are clearly visi- 
ble; the skin is tightly drawn over the skeleton; the coat is rough 
and without luster; the animal remains almost constantly standing; 
the nose is raised and the head extended on a line with the neck; the 
elbows are turned out to facilitate the expansion of the chest; the 
eyes are sunken, and there is a haggard expression to the face in 
harmony with the general appearance of the bod}-. 

The symptoms of tuberculosis in hogs are very obscure and difficult 
to detect. In the great majority of cases no symptoms are noticed 
and the disease is only recognized l)y an examination of the carcass. 
The parts most frequently affected are the glands of the neck, the 
bronchial, mediastinal, mesenteric, and portal glands, the liver, lungs, 
kidneys, and spleen. In numerous cases the glands of the carcass are 
affected, and tuberculosis of the bones and joints is common. 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 23 

Altliouoh tlici'e is a o-reat tendenc}' for tuberculosis to spread to 
different parts of the body in swine, causino- it to become more fre- 
quently o-eneralized with these animals than with cattle, the rapidity 
with which they take on fat apparently enables them to resist the 
destructive inffuence of the disease, at least to the age at wdiicli they 
are general I3' slaughtered. Animals which come to market fat and 
appear perfecti}' well just before slaughter may be found ([uite 
seriously diseased. 

In some cases, however, swine may show enlargement of the glands 
of the neck and of other parts of the body, diarrhea, emaciation, and 
tubercular inflammation and swelling of one or more joints. When 
the nutrition of the body is affected, as shown by loss of flesh, the 
disease nsuall}' runs a rapid course and causes the death of the animal 
in a few weeks. 

EFFECTS UPON A HERD OF CATTLE. 

It is no less important to stud}^ the effects of tuberculosis upon a 
herd of cattle than to study its effect upon the individual animal. The 
experience of those who have had herds free from the disease but who 
have had the misfortune to introduce it and have seen it develop among 
their animals must be of the greatest value to others who desire to 
guard against it. A number of such cases have ))een carefull}^ studied 
at the experiment stations and elsewhere and the principal features of 
the outlu'eaks ascertained. 

AN EXPERIMENT WITH TI'BERCrLOrS CATTLE. 

Phelps'^* relates experiments with four condemned cows which were 
placed by the Connecticut State cattle commission at the disposal of 
the Storrs Experiment Station for the purpose of making some obser- 
vations and experiments on bovine tuberculosis. The herd from 
which these animals came had been officially tested in March, 1896, 
and several animals in the herd were condemned and slaughtered, 
although the four cows mentioned failed to respond and were tagged 
as free from the disease. In October, 1896, the herd was tested again 
by the commissioners, and these four cows responded and were then 
condemned as tuberculous. Shortly afterwards they were brought to 
the station and were kept in quarantine until they were slaughtered in 
the fall of 1900. 

These particular animals were chosen for the experiment because 
there was good reason to believe that the disease was present in its 
earlier stages. While the cows were at the station they were kept 
isolated from other cattle in a high, light, and airy stable w^th about 
1,500 cubic feet of air space per cow, although later several calves 
which were used in the experiments with the cows occupied the same 
stable. Adjoining the stable was a small yard about one-half acre in 
area in which the animals were allowed to exercise several hours each 



24 TUBERCTTLOSIB OF THE FOOD-PRODUCING ANIMALS. 

day, except in very stormy or extremely cold weather. No special 
treatment for the disease was attempted, but good care and feed were 
affoi'ded at all times. During- the first year that the animals were 
under observation all four cows remained in good condition and showed 
no outward sign of disease. It is evident that these cows were received 
at the station soon after their infection, when the disease had made 
but slight progress and l)efore the general health of the animals was 
noticeably affected. They were kept under excellent sanitary condi- 
tions, with outdoor exercise and good food, and were protected from 
the worst weather. The}^ shoidd, therefore, have done much better 
than the average farm cow after it is infected with this disease. 

The history of these cows at the station is ver}- instructive, and is. 
in brief, as follows: 

Cow No. 1337. This cow produced a vigorous calf April 5, 1897. The calf suckled 
its dam for six moutlis, and Avas then placed in the college herd. During 189<S the 
cow apjieared to be in vigorous health and remained in good condition of tiesh. She 
dropped a well-developed calf in Septemlier, 1898, which was allowed to suckle its 
dam for al)Out a year. During 1899 she remained in a vigorous state of health, and 
produced a healthy calf in December, 1899. Although this calf appeared vigorous 
and strong at birth, it was soon after attacked by scours and died in a few days. 
During 1900 the cow remained in good flesh, had a sleek coat, and continued to give 
a good flow of milk. Early in the year she developed a slight cough, but otherwise 
appeared in perfect health when killed in November, 1900. Examination of the car- 
cass showed the me<liastinal lymphatics to be tuberculous, and a tuberculous nodule 
was found in the riglit lung. The other organs were normal. 

Cow No. 1341. This cow dropped a dead calf in 3Iarcli, 1897, the carcass of which 
was carefully examined, but revealed no signs of tuberculosis. She produced a well- 
developed calf in August, 1898, and seemed to be in a good state of health through- 
out the following winter. During 1899 she remained in fair flesh and gave a good 
flow of milk until July. At that time, while being fed green oats and peas, she was 
attacked by scours and began to run down rapidly. Siie ceased giving milk for a 
short time, but when placed on dry feed began to regain flesh and milk flow. She 
remained in a fair state of health during the fall, but had a tendency to looseness of 
the bowels. A healthy calf was produced in February, 1900, which was followed by 
a good flow of milk for several months, but during the spring and summer she lost 
flesh rapidly until her flanks were hollow and her ribs protruded plainly. The coat 
became rough, the eyes dull and sunken, the cough increased, and the breathing 
became more frequent. This cow continued to scour intermittently, and when killed 
in November, 1900, was generally emaciated, although continuing to give milk up to 
the time of her slaughter. Two-thirds of the riglit lung and one-half of the left lung 
were fllled with tuberculous tissues and the mediastinal lymjihatics wei'e diseased. 

Cow No. 1343. This animal became quite fat during the early part of 1898. She 
dropped a rather small calf in August, 1898, and was considerably thinner than usual 
for three months after calving, but soon after that began to gain in flesh. Later in 
the fall it was noticed that she had a persistent cough. During the spring and sum- 
mer of 1899 she continued to give a fair flow of milk, but was not as fat as in 1898. 
Her cough increased during the Avinter of 1898-99, ancl in the following spring it was 
noticed that she coughed badly after eating dry feed or when made to exercise vig- 
orously. However, she i)roduced a vigorous calf in December, 1899, but this Avas 
soon after attacked by a mild form of scours, from Avhich it recovered. She gave a 
fair flow of milk during the early part of the year 1900, although she Avas losing flesh 
and had an increasing cough and short, hurried breathing. During the fall of 1900 
she lost flesh rapidly, had a rough coat, sunken eyes, and protruding ribs. She lost 
her appetite, and in October ceased to give milk, and Avhen slaughtered in November 
was very much emaciated. Up to Avithin a year of the time of slaughtering, this cow 
had been the fattest and sleekest of the four. The examination of the carcass showed 
both lungs badly diseased, almost solidified Avith tuberculous tissue, the chest walls 
covered Avith tubercles, and the mediastinal and mesenteric lymphatics badly tuber- 
culous. Tubercles were found on the rumen and the diaphragm. 

CoAV No. 1344. This coav remained farrow during 1898, but continued to give a 
good fk)AV of milk. During the fall of 1898 she gained in flesh and appeared to be in 



MATERIAL FAOT^^ CONOEENlNd TTTKERCTLORTS. 



25 



a healthy and vigorous condition, h^hc veuuiined in this condition until yonie time 
in the summer of 1899, when she showed lameness in the right stifle joint. She 
calved in October, 1899, but the calf was weak at birth, and refused to eat. It died 
about a week after birth. The cow gave a good flow of milk for several months aftei' 
calving, l:)ut was thinner than usual. During the early part of 1900 she lost flesh 
rapidly, though still giving a good flow of milk. She also developed a severe cough, 
which was esjiecially noticeable when she Mas made to exercise vigorously. The 
lameness in the stifle joint increased in severity and became very troublesome to the 
cow. She lost flesli during the summer and fall, and, although not as emaciated as 
Nos. 1341 and 1342, was quite thin, had a rough coat, and appeared to be in a l)ad 
physical condition when slaughtered in November, 1900. The examination of the 
carcass showed the mediastinal lymphatics diseased and an abscess in the left lung. 

With three of the four cows in this experiment tlie disease pro- 
gressed from the veiy earliest stage to a point where the animals were 
worthless within about four years. ^Mth tlie fourth animal it 
remained nearly stationary and did not apparently' affect the general 
health. 

SPRE.\n OF TUBERCULOSIS HY DISPERSIOX SALE. 

Russell "'^ gives the following example of the dissemination of a dis- 
eased herd: 

In October, 1903, a public sale was held in one of the southern counties of Wiscon- 
sin, at which a herd of 4tj head of cattle were disposed of in order to divide up the 
interest of the landlord and the tenant. These 46 head were jjurchased by twelve 
persons. The landlord, wishing to retain what he thought were the most valuable 
animals, had a friend buy in for him 18 head, while the tenant bought 3 for himself. 

One of the ])arties who had purchased 6 of these animals decided in the following 
Februarj' to have his herd tested for tuberculosis. A neighbor, hearing that the test 
was to be applied, asked to have his family cow tested at the same time. The result 
of the test was to show positive reactions in the case of this single animal and also 
in 3 out of the lot of 6 which had been jiurchased. This revelation led the original 
owner to investigate the condition of the jjortion of the herd which he had pur- 
chased, and in this case 14 of the original 18 were found to be affected. 

The matter at this stage was brought to the attention of the State live stock sani- 
tary board, and after a lapse of some weeks, so as to secure normal results, retests of 
tliese herds were made. In addition, all the herds were tested into which any animal 
ha<l l)een introduced from the herd dispersed at the sale. The results of these tests 
are shown in the following table: 

DIssenunalion of tuberculosis irito various licrds bij Sdle of siock. 



Herd. 


Number of 

animals in 

herd. 


Number of 
animals 

from origi- 
nal herd. 


Number of 
tuberculin 
reactions. 


Number of 
reactions 
in animals 
purchased. 


1 


21 
18 
38 
8 
5 
3 
1 

15 
32 
18 
2 
2 
22 


5 
18 
6 
3 
2 
3 
1 
1 
1 
3 
1 
2 
9 


3 

14 
3 
4 
2 
3 
1 
1 
1 

1 
2 
1 


3 


2 


14 


3 


3 


4 


2 


5 


1 


6 ... .. .. 


3 




1 


8 


1 


9 


1 


10 





11 


1 


12 


2 


13 


1 







It is evident from the above data that the originally affected herd 
was badly diseased, as 33 out of the total number of 55 disposed of at 
the sale or before responded to the tuberculin test. And yet none of 
these animals showed any appearance of the disease, and no one ques- 
tioned their healthy condition at the time of purchase. The fact that 



2B TITIiEROTTLOSrs OF THK FOOD-PRODITOING ANIMALS. 

the owners bought in ji large portion of the herd i,s evidence tiiat thev 
had no idea of the existence of this serious disease. 

It was exceedingly fortunate tliat the first test happened to be made 
so soon after the sale of this herd, as the disease had apparently just 
})egun to spread in the herds to which the animals from it were taken. 
It is, nevertheless, a good example of the extent to which the infection 
may be disseminated ])y the sale of animals from a single herd which 
is apparently in healthy condition. 

HISTORIES OF AFFECTED HERDS. 

The following history of the introduction and development of the 
disease in the herd of the Connecticut Agricultural College is a strik- 
ing example of the danger of purchasing cows so long as tuberculosis 
is prevalent in dairy herds:"'' 

Previous to 1896 the lierd consisted of grade animals, mostly of Jersey and Guernsey 
blood, but in that year 15 registered Jerseys, Guernseys, and Ayrshires were pur- 
chased. Since then the acquisitions to the herd have been from the natural increase 
of these animals, and the occasional i)urchase of grade cows. The herd was exam- 
ined by the veterinarian and tested with tuberculin in 1896. The registered animals 
purchased during the year were also teste<l, and the herd was pronounced free from 
tuberculosis. The tuberculin test was applied again in 1897, with no reactions. 

In October, 1897, several grade cows were purchased, including " Fannie," a grade 
Guernsey. This cow was bought of a neighboring farmer, who had owned and 
raised her from a calf. Her owner reports that he had never had tuberculosis in his 
herd and had never used the tuberculin test. Fannie was a smooth, plump cow, 
and apparently in perfect health. When purchased she was tested with tuberculin, 
and, as she did not respond, was given a permanent place in the herd. She remained 
apparently in good health until about November 1, 1898, when she began to refuse 
a portion of her allowance of silage, and soon after commenced to scour, but at no 
time did she cough. From this time on she ran down rapidly, and was killed on 
November 20, as it was evident that she could live but a day or"two longer. A post- 
mortem examination showed a generalized and advanced case of tuberculosis. The 
herd was tested with tuberculin December 28, 1898, when 12 animals responded; it 
was again tested May 22, 1899, when 3 more responded; it was tested for the third 
time December 7, 1899, when 2 more responded; and it was tested for the fourth 
time April 16, 1900, when 1 additional animal responded. No further reactions 
occurred in subsequent tests, the last of which recorded was made on February 17, 
1902. 

Including the original tuberculous animal, there were, consequently, 19 diseased 
animals found in this heard of 49 animals, the disease having spread to that extent 
in about two and one-half years, notwithstanding that it was discovered at the end 
of the first year, and that affected animals were removed as fast as they were 
revealed by the tuberculin test. 

RusselP gives the following histor}^ of an extensive outbreak of 
tuberculosis among cattle which recently came to light in the herd of 
a prominent dairyman supplying milk to the city of Beloit, Wis. : 

The owner had a fine dairy farm on the outskirts of the city, and had constructed 
ample stable room to accommodate his herd. The business "had developed until at 
the time of examination 70 animals were kept, 46 of which were in milk. A veter- 
inary examination of an animal somewhat out of condition revealed the presence of 
tuberculosis, much to the surprise of the owner, and the tuberculin test was then 
applied to the whole herd. 

Fifty-seven in this herd of 70 reacted to the test. Those that escaped were for the 
most part young stock. Thirty-three of the best conditioned of the 57 reacting ani- 
mals were shipped to abattoirs for immediate slaughter, and of this number only 18 
passed Federal inspection. Of the 24 killed on the farm not to exceed 7 would liave 
passed for beef had they been sent for slaughter. Thus it appears that 32 of the 57 
that reacted were so badly affected as to require total condemnation of the carcasses. 



MATERIAL FAOTS ('ONOERNINfl TITBEROULOSIS. 27 

The owner was in CalifDi'iua, but it was adiiiitted by the herdsman who had 
handled the herd in previous years that a considerabh? nund)er of animals had died 
or been killed from year to year as long ago as 1897. Fretjuently animals had l)eeu 
shot to get rid of them as they pined away. No examination was made and the 
matter was allowed to drift on until the startling revelation was made by the use of 
the tuberculin test. The slaughter of this herd revealed many cases of advanced 
tuberculosis, and in some instances even the udders were found diseased. The farm 
had well-constructed barns and stables, which were kept in a clean and sanitary 
manner, but no provision was made for ventilation. 

Within a week from the time this first-mentioned herd was disposed of, another 
was examined in the southern part of the State in which even a worse condition was 
found. In this instance the herd consisted of 72 animals, many of which were fresh 
in milk, as the product was to sujiply a Swiss-cheese factory. The condition of the 
stock revealed by the tuberculin test was shocking. Of the 72 animals tested, 69 
reacted. Only 1 mature animal, a yearling bull, and a young calf escaped the 
disease. 

This widespread distribution of the disease was found to be due to the usual cause, 
neglect and failure to provide jjroper sanitary surroundings. For several years the 
owner had been losing animals from time to time, but made no effort to learn the 
cause of the trouble. This last winter 5 died, the year before 2 others, and during 
previous years still others. Four years ago he sold to a neighbor 5 head of young 
stock, which were kept on pasture during the summer. In the fall they weighed 
less than when bought, and were condennied when shipped to Chicago. Later 7 or 
8 others were bought for shipment, .'5 of which were condemned when inspected. 

The post-mortem findings in this herd revealed many cases of generalized tuber- 
culosis, some of which were in a most aggravated form. In a number of cases the 
udders showed well-marked physical signs of disease. The development of the dis- 
ease in young stock in both lung and body cavities, with the infection of the bowel 
itself, bespoke a doulale infection, through the milk as well as through the air. The 
stable in which this entire herd of 70 head was kept, with al)out a dozen young 
calves, was located in a stone basement, in whii'h there was absolutely no provision 
for ventilation. A little light filtered in through five or six tightly closed sash win- 
dows of three 8 by 10 inch panes of glass to each window. The interior of the stable 
was so dark that one could scarcely see to read ordinary newspaper print unless the 
doors were left open. In addition to these general insanitary surroundings, the 
manure on the fioor of the stable was over a foot thick. 

The way these two herds were handled is markedly contrasted with the course of 
action that was pursued in the following case: 

A few weeks ago a member of the farmers' course at the Agricultural College wit- 
nessed a demonstration of the tuberculin test, and while he had no reason to suspect 
the presence of the disease in his own herd, he went home with the thought that it 
would be prudent for him to apply the test and satisfy himself as to the actual I'on- 
dition of his animals. In his herd of 25 only 1 was found affected, and this was a 
registered cow that had been bought a few months before f(tr the sum of $150. This 
animal was the only recent purchase that had been made. 

Recently another correspondent wrote that he applied the test to his iierd, and 
found that 3 out of 5 registered Holsteins that he had purchased a short time before 
at an expense of |1,500 were affected. 

THE CAUSE OF TUBERCULOSIS. 

THE TUBERCLE BACILLUS. 

Tuberculosis is caused by a bacterial oro-anism known as the Bacillus 
tuhe7'cvJ(>8is imcroha^ which.^ so far as is known, does not nutltiply out- 
side of the animal body except under the artificial conditions supplied 
in laboi-atories. As we find the bacillus in the body of an animal it is 
very exacting in the conditions which it requires for its growth, and 
for a long time bacteriologists found it difficult to make it develop in 
their lal)oratory cidtures. Careful study of its peculiarities has, how- 
ever, resulted in the discovery of methods by which it is now easily 
isolated from the tissues of the affected animals and grown in pure 
cultures. The longer it is grown in the laborator}^ the more readilj^ 



28 TUBERCULOSTS OF THE EOOD-PRODTTCING ANIMALS. 

it is ciiltivtitetl, as it adapts itself <;-radually to the new eonditioiis; but 
in aequiriny- this exalted power to live and multiply outside of the 
animal body it generally loses some of its disease-producing- power 
and becomes less and less virulent until in the course of time it may 
not be able to cause disease in the most susceptible animals. 

The tubercle bacillus produces tuberculosis in all species of domesti- 
cated animals and probal)ly in most species of wild animals, though 
some species of animals are very much more susceptible to its effects 
than others. It is able to multiply in the bodies of birds whose tem- 
perature is considerably higher than that of mammals, and it is like- 
wise able to nudtiply in the bodies of cold-blooded animals whose 
temperature is far Ijelow that of mammals. It therefore lives, propa- 
gates itself, and causes disease under a great variety of conditions — a 
variety which is truly surprising when we consider the delicacy of the 
germ and the difficulties which were encountered in cultivating it in 
the lal)oratory. 

The tubercle bacillus as it is found in widely ditferent species of 
animals is not always identical in its characteristics, although there are 
certain general features which it always retains. Its peculiarities in 
regard to staining are the most striking of these. It does not take up 
the usual stains which are successful with other bacterial organisms, 
and consequently must be stained by special methods. Koch first suc- 
ceeded in coloring it by leaving it for several hours in a solution of 
methylene blue, to which caustic potash had been added; but this 
method was soon superseded by a solution of gentian violet in water 
saturated with anilin oil, which was introduced by Ehidich. Of late 
years carbol-fuchsin has been quite generally adopted for this purpose. 
Another peculiarity of the tubercle bacillus is that having once taken 
a stain, it fixes it very firmly, and it is, therefore, much more difficult 
to decolorize than other bacilli. The dilute mineral acids will remove 
these colors from animal substances and from other bacteria, but not 
from the tubercle bacilli. Advantage is taken of these peculiarities to 
make luicroscopic preparations in which the tubercle bacilli appear 
brightly stained while everything else is free from color, or to make 
these preparations so that the tul)ercle bacilli will appear red and all 
other micro-organisms will be blue. 

The tubercle bacillus obtained from human beings is able to grow 
between the temperature limits of 30- and 40° C. ; that obtained from 
birds is able, to grow between the limits of 25"^ and 45° C. ; while a 
stock of tubercle bacilli obtained by Friedmann from a tuberculous 
turtle was able to multiply at the freezing point and its temperature 
limits were placed by the discoverer at 0° to 43° C. The bacilli from 
these different sources have different habits of growth in cultures, and 
some under the microscope appear longer, thinner, and more beaded 
than others. There is also a oreat difference in the virulence of the 



MATEETAL FACTS CONCEKNING TUBERCULOSIS. 29 

various stocks for different species of animals. Human bacilli are only 
with difficulty made to produce disease in fowls or in cold-blooded ani- 
mals, and the greater muuber of such stocks have little or no effect upon 
bovine animals. Various investigators have succeeded, however, in mod- 
ifying the different stocks of bacilli, and have been al)le to infect success- 
fully birds and cold-blooded animals with human and bovine ])acilli, 
and have also infected mammals with the tubercle bacilli of birds. 

It appears, therefore, that the tuberculosis liacillus is one which is 
able to adapt itself to a wide range of conditions, and that the bacillus 
as found in the tul)erculous lesions of ))irds, mammals, and cold-blooded 
animals is the same organism but moditied somewhat l)v the conditions 
of environment. 

MANNER OF INFECTION AND DEVELOPMENT OF THE DISEASE. 

The tubercle l)acillus may enter the body through a number of chan- 
nels and thus cause infe(J:ion. With cattle it is most frequently drawn 
into the air tu))es in the form of dust floating in the atmosphere of the 
stable. In many cases, however, it enters into the alimentar}^ canal 
with food that has been soiled with the saliva or other secretions of 
diseased animals. It may also gain entrance through a milk duct or 
through the vaginal opening, or by means of a wound. The bacillus 
appears to be al)le to penetrate the mucous membranes, at least in cer- 
tain places, even when there is no wound or abrasion, and it may pass 
through the membrane without leaving aiiv tubercular material or 
other sign to show where it gained entrance. However, in its progress 
through the tissues it is usually soon arrested either by a lymphatic 
gland or in some other manner, and then it nudti})lies and causes the 
formation of a tubercle. The channel ))y which the infection occurred 
may gBnerally be determined with some degree of certainty ])y the 
location of the older tubercles. If the bronchial or mediastinal glands 
show the earliest lesions the infection probably came through the in- 
spired air; but if the retrophaiyngeal, mesenteric, or portal glands 
have the oldest lesions the infection was probably through contami- 
nated food. 

When the tubercle Ixicilli have lodged in or invaded any organ their 
irritating effect upon the tissue surrounding them sets up changes 
similar to those seen in ordinary infiannnation. The ffxed connective 
tissue cells and the cells of the endothelium of the capillaries begin to 
multiply and produce large numbers of new cells which group them- 
selves side l)y side in the form of a hollow sphere around the bacilli. 
These cells are then called epithelioid cells, and for the reason tliat it 
is composed of such elements the tubercle at this early stage is known 
as the epithelioid tubercle. 

After the tubercle has made some progress in its development l)y 
the process just described and has become barely visil)le to the naked 



30 TUJiERCTTLOSTS OF THE FOOD-PRODUCING ANIMALS. 

eye, .snuill round cells, called by some l^^raphoid cells, begin to gather 
around the sphere of epithelioid cells and ma}' become so numerous as 
to obscure the latter and cause their disappearance. These round cells 
undou))tedl3' come from the blood vessels in the vicinity which have 
been affected l»y the adjacent tuberculous growth. When these lym- 
phoid cells have increased in number until they predominate in the 
newly formed tubercle, this is called a lymphoid tubercle. 

When the tubercle develops to about the size of a pin head, the 
lymphoid cells have usualh^ become so numerous that they interfere 
with the mitrition of the central portion, and, therefore, the cells 
located at the center begin to die. As the cells die they disintegrate, 
and there is formed a granular, caseous material from which the bacilli 
have disappeared. When this process occurs slowly it is accompanied 
by the formation of giant cells, thac is, large cells containing numer- 
ous nuclei. These cells are formed either l)y the fusion of a number 
of cells together or by an abnormal increase in the protoplasm of a 
sing-le cell together with the multiplication o^ its nuclei. 

As the tubercles increase in size, either by the addition of more cells 
or b}' the fusion of two or more small tubercles, the necrosed and 
caseated portion at the center })ecomes larger, and as this process con- 
tinues tubercular masses of considerable size may be formed, having 
the same g-eneral appearance as the smaller tubercles, l)ut with a rela- 
tively larger proportion of caseous material. 

When the center has undergone partial caseation, the epithelioid 
cells surrounding the tubercle may be gradually changed to connective 
tissue cells, which are deposited in successive layers and thus form a 
tibrous wall. By the time the former cellular elements of the tubercle 
have disappeared this tibrous wall or capsule becomes hrm and resist- 
ant and completely isolates the necrotic focus. 

The caseous material wdthin the tubercular mass mav soften and 
form a li(juid resembling pus, or there may be a deposition of calcare- 
ous salts which at first form as small angular granules and later co- 
alesce into larger nodules until finally the entire caseous material may 
be calcified. This change is very common with both cattle and hogs. 

After an animal has been infected with tu})ercle bacilli and the first 
tubercle has commenced to develop in the manner above described, 
more or less bacilli may be carried from this first point of infection 
with the streams of lymph or blood and lodge elsewhere to cause the 
formation of other tubercles. When the l)acilli are carried through 
the lymph channels they usually are deposited before going any great 
distance, and hence, in this case, the tubercles are limited to one organ 
or to one part of the body; but if the bacilli penetrate the blood ves- 
sels in great numbers, as sometimes occurs, they are carried to all 
parts of the body and generalized tuberculosis is the result. 

The ways in which tubercle bacilli escape from the l)ody art^ quite as 



MATEKIAL FACTS CONCERNING TUBERCULOSIS. 31 

intei'esting- from a practical point of view as the ways in which the}^ 
enter it. There are a number of channels through which they may 
be disseminated, but the most common ones arc the air tui)es, the 
digestive tube, and the milk ducts. Tubercles which develop near 
these channels, or in the mucous membrane lining- them, may soften 
and discharge their contents into the tubes. In the case of the air 
tubes the material is coughed up, contaminates the saliva, and is partly 
distril)uted in the mangers and racks, and over the litter, and partly 
swallowed to pass away with the excrement. In the case of tubercu- 
lar ulcers on the internal surface of the intestine, or of cavities in the 
lung opening into the bronchi, or of similar lesions conmiunicating 
with the milk ducts, there may be a continuous development of the 
bacilli and an equally continuous discharge of vast numbers of these 
germs into the intestine, the bronchi, or the milk ducts, as the case 
may be. An animal so alfectcd is most dangerous and may soon infect 
most of the individuals in the herd. The bacilli are less frequently 
distributed from the genito-urinary organs, although such distribution 
may occur when the kidneys or uterus are the seat of the disease. 

On the other hand, the tubercular lesions ma}" l^e so situated that 
the}" are closed in and have no channels of communication with the 
exterior, as in those cases where the 3^ are confined to a bronchial, 
mediastinal, or mesenteric lymphatic gland. Under such conditions 
an affected animal may remain in a herd for a long time without com- 
municating the disease to the other animals of the herd. But prob- 
ably in the majority of such cases there will sooner or later be an 
extension of the tubercular formation in the affected animal, wdien it 
ma}" suddenh' and without warning begin distributing the bacilli and 
infect the animals which are stabled or pastured with it. This explains 
wh}' in some instances a tuberculous cow may infect the greater part of 
a large herd within a few months, while in other instances such a cow 
may remain in a herd for several years and no other animals become 
infected. The disease is of the same nature in both cases, l)ut in one 
case the })acilli are able to escape f I'om the body of the diseased animal, 
while in the other they are imprisoned and unable to do further harm. 

INFECTIVENESS OF MILK OF TUBERCULOUS COWS. 

The milk of tuberculous cows is a very common medium for cariy- 
ing the tubercle bacillus to other animals, for while every cow affected 
with the disease does not secrete milk contaminated with the bacillus, 
there are frequently one or more cows in an infected herd whose milk 
is infected, and this, in turn, infects all milk with which it is mixed. 
There has been a great difference of opinion as to the proportion of 
affected cattle which yield milk containing the tubercle bacilli. Some 
have held that the udder nmst necessarily be diseased before the bacilli 
can find their way into the milk ducts, and as only a small proportion 
of the affected cows have disease of the udder, the danger from this 



32 TUBERCTTLOSIS OF THE FOOD-FRODUOING ANIMALS. 

source was thoug-ht to be slight . It seems likely, however, that the 
udder is affected in a larger number of cases than has usuall}^ been 
admitted. It requires a very long- and careful examination to deter- 
mine positively that the udder is free from the disease. The European 
statistics have usually given the proportion of udder tuberculosis as 
from li to 3 per cent of the total number of cases; but Pearson, in the 
examination of 1,200 tuberculous cows in Pennsylvania, found the 
udder affected in 8.75 per cent of the animals. 

Numerous investigations have also shown that milk may contain 
tu])ercle bacilli when there are no appreciable signs of tubercular 
disease in the udder. A few of the more striking of these may be 
mentioned. Bang^' tested the milk of 21 tuberculous cows with nor- 
mal udders by inoculating- -±8 ra))l)its. Two, or 9.5 per cent, of these 
cows transmitted the disease. Later he injected -10 guinea pigs with 
milk from 28 cows affected with generalized tuberculosis and showed 
that virulent milk was being secreted by 4 of these animals, 3 of which 
on post-mortem examination were found to have lesions in the udder. 
B}^ intra-abdominal inoculations of 28 guinea pigs with the milk of 14 
tuberculous cows he found that 3 of the latter were excreting tubercle 
bacilli in their milk. The summary of these experiments shows that of 
63 cows 9 g-ave virulent milk, and of this number 3 had tuberculous 
udders, leaving 9.5 per cent of the cows with normal udders producing 
infectious milk.'"'* 

Ravenel " experimented with 5 cows which reacted to tuberculin but 
showed no physical signs of tuberculosis. The udders in every case 
were free from disease so far as a careful inspection could reveal. The 
post-mortem examination of these cows confirmed the diagnosis made 
during life. He inoculated guinea pigs with a single dose, averaging 
10 c. c. of milk from these cows. In the first series of experiments 4 
out of 31 guinea pigs, or 12.9 per cent, became tuberculous. In the 
second series of experiments 5 out of 24 guinea pigs contracted tu])er- 
culosis, a percentage of 20.8. In the third series, in which the milk 
of a single cow was employed, 1 guinea pig out of 8 became tuberculous, 
or 12.5 per cent. In these three series of experiments 10 guinea pigs 
out of 63, or 15.8 per cent, became infected by a single dose of milk 
from these cows which apparently had no disease of the udder. 

Raliinowitsch^" and Kempner succeeded in producing tuberculosis 
in guinea pigs with the milk of 10 out of 15 tuberculous cows, or 66.6 
per cent. Two of these cows were later found to have tuberculous 
udders, 3 showed advanced generalized tuberculosis, while the remaining 
5 animals were but slightly affected. The writers conclude that milk 
from cows with incipient tuberculosis, but without disease of the udder, 
may contain tubercle bacilli; also that in latent forms of tu])erculosis 
the milk may prove infectious, although the cow may not present any 
clinical symptoms of tuberculosis; and therefore that milk from all 
cows reacting to tuberculin should be considered as at least suspicious. 



MATEBIAL FACTS CONCEElSriNG TUBERCULOSIS. 33 

It is believed by Adarai''" that the cells of an actively secretino- 
mammary gland of a cow can take up and discharge the tubercle 
bacilli without the animal showing any lesion of the lacteal tract. He 
and Martin examined the milk of 10 cows, and when these were killed 
the udders were subjected to microscopic examination with negative 
results. In the milk of 6 (00 per cent) of these cows tubercle bacilli 
were observed by the aid of the microscope. The milk from the cow 
showing the greatest number of bacilli was inoculated into 2 guinea 
pigs, and both died as a result of the infection. Twenty-nine guinea 
pigs and 26 rabbits were inoculated with varying quantities of milk, 
and 1 calf was fed for five months, but onl}' 2 guinea pigs died of 
tuberculosis. 

Gehrman and Evans ^' found tubercle bacilli in the milk of 16 out of 
41 cows with sound udders, or 36.6 per cent, (juinea pigs inoculated 
with milk from 10 of these cows died of tuberculosis (24.3 per cent). 
Their final showing- is that 16 of the cows, or 39 per cent, at one time 
or another, gave milk containing tubercle bacilli. 

The milk of 56 reacting cows which showed no signs of disease of 
the udder was carefully tested in various waj^s by Mohler and 
Norgaard.'^'^ One or more of the guinea pigs fed with milk from 9 
diiferent cows out of this lot succumbed to typical tuberculosis — that 
is, the milk of 16.07 per cent of the 56 reacting cows was found to be 
pathogenic to guinea pigs when fed to them. 

Of the experimental animals inoculated intra-abdominally in the first 
series, at least 1 guinea pig died of tuberculosis in each of six dif- 
ferent instances, showing that the milk of 10.9 per cent of the 55 
reacting cows in this experiment was fatal to guinea pigs. In the 
second series of intra-abdominal injections, the milk from 7 individual 
cows out of 45 examined, or 15.5 per cent, was demonstrated to pos- 
sess virulent tu))ercle Imcilli. By uniting these inoculation results, it 
is found that 11 out of 55 cows, or 20 per cent, secreted milk which 
transmitted tuberculosis to one or more experimental animals when 
injected into the peritoneal cavity. 

The combined results of the ingestion and inoculation experiments 
showed that the milk of 12 out of 56 reacting cows, or 21.4 per cent, 
at one time or another, during the experiment contained virulent 
tubercle bacilli. 

Specimens of the mammary glands from all the cows j'ielding this 
virulent milk were brought to the laboratory and histological exami- 
nation was made of them without finding any indication of tuberculosis. 
With one of these cows positive results were obtained in all of the 
tests — that is, by ingestion, by inoculation, and by miscroscopic 
examination of the sediment of the milk and cream — although but T 
of the 10 experimental animals fed and inoculated with the milk of 
this cow became tubercular. It was evidently a case in which the milk 
1881— No. 38-06^—3 



34 TUBERCULOSIS OF THE FOOD-PRODUCHSTG AJSTIMALS. 

was seriously contaminated. Special attention was given to the exami- 
nation of the udder of this cow and numerous serial sections were 
examined, with entirel}' negative results. 

"The results of these careful experiments p^ove that the milk from 
a considerable proportion of reacting cows contains the tubercle 
bacillus and is capable of producing tuberculosis in animals which 
consume it. The proportion of cows which yield such infected milk 
is much greater than the proportion which show tuberculosis of the 
udder. Whether the milk in these cases was actually infected within 
the udder or whether it became contaminated at the time it was drawn 
makes little practical difference. Every precaution was taken to pre- 
vent such contamination after the milk left the mammary gland, and 
if the bacilli floating in the air of the infected premises or dropping 
from the coats of the animals infected the milk in spite of the precau- 
tions that were taken, similar infection would certainly occur in 
ordinary dairy opin-ations. It must be admitted, therefoi'e, that the 
milk from tuberculous cows is often infected and dangerous when, so 
far as can be ascertained, the udder is in a normal condition. 

The milk from tuberculous herds is a frequent source of tubercu- 
losis in calves and pigs. The calves born in tuberculous herds are fed 
upon the milk produced by such herds during the early period of their 
lives, and a considerable proportion of them may be infected in that 
way. In dairies where butter is made, or from which cream is sold, 
the skim milk is commonh^ fed to pigs, and in other cases skim milk 
is obtained from creameries for feeding to calves and pigs, and the 
animals are often infected in this way. 

Pearson and Ravenel,'^ in treating of the ways in which tuberculosis 
maybe spread, say that the mixed skim milk returned from a creamer}- 
to a healthy herd may be contaminated. This danger is so great that 
in some places (parts of Pennsylvania and New England, France, and 
Germany) it is the practice to heat skim milk to a temperature that 
will insure the destruction of the tubercle bacillus. In Denmark and 
Prussia such heating of skim milk and buttermilk is required b}^ law. 
Several illustrations of this danger had recently come under the obser- 
vation of these authors. In one case a large herd was tested with 
tuberculin and found to be extensivel}^ diseased. Two of the cows had 
tubercular udders. This herd was used for the production of cream that 
was shipped to market, the skim milk being retained for feeding calves. 
It was the practice on this farm to remove the calves from their dams 
when they were three daj^s old and keep them in a separate building 
distant from the cow stable. The dairj- building and separator were 
located midway between the cow stable and the calf stable. After 
the cream had been separated the skim milk was carried on for the 
calves. When the cows were tested the calves were also examined, 
and it was found that while the prevalence of tuberculosis among the 



MATERIAL FACTS CONCERlSriNG TUBERCULOSIS. 



35 



dairy cows was 75 per cent, all the calves reacted and were condemned. 
The post-mortem examinations of the calves revealed tuberculosis of 
the postpharyngeal lymphatic glands or lower digestive tract in all 
cases, indicating that infection had occurred through the digestive 
system and that it had been carried to these calves in skim milk. 

Only a small proportion of the calves dropped by tuberculous 
mothers are affected with tuberculosis at the time of birth. In other 
words, the cases of congenital tuberculosis are very rare. Klepp 
found at the slaughterhouse in Kiel among 4,068 calves that were 
slaughtered onl}" 20 affected, or CCtt per cent, and in a second series 
of investigations there were found 10 calves affected with congenital 
tuberculosis among 847, a proportion of 1.18 per cent. Hoy berg 
obtained similar results, having found 6 cases of congenital tuberculo- 
sis among 500 calves examined at the time of shxughter. According 
to the calculations of Klepp only 2.03 per cent of the calves dropped 
by tuberculous mothers are affected with congenital tuberculosis.^^ 

As an example of the proportion of calves found aff'ected, Bang^"^ 
gives the statistics of the small slaughterhouse at Aarhus, Jutland, 
where ver}^ careful examinations are made and where the cattle come 
from a district in which tuberculosis is very widely disti'ibuted. In 
the 3^ear 1903 there wore found among 0,705 calves (3,279 quite young- 
calves and 3,484 fat calves) 100, or 1.48 per cent, tuberculous (with 14 
new-born calves the existence of congenital tul)erculosis was discov- 
ered). Among 4,920 grown cattle there were 2,509 tuberculous, or 
51 per cent. 

It would appear from these figures that possibl}^ not more than 
1 per cent of the calves from tuberculous mothers are affected with 
tuberculosis at the time of birth. In ver^' badly aff'ected herds as high 
as 2 per cent of the calves may have congenital tuberculosis. Under 
any circumstances, it is plain that the great majorit}^ of calves contract 
the disease either from contaminated milk or from inhabiting the stables 
where tuberculous cows are kept. 

Bang"" gives the following table showing the distribution of tuber- 
culosis according to age in 40,024 cattle tested for the first time in 
Denmark during the vears 1898-1904: 



Age when tested. 



Number 
tested. 



Number 
which 
reacted. 



Per cent. 



Calves up to one-half year 

Cattle from one-half to Ij years 

Cattle from li to 2k years 

Cattle from 'ij to 5 years 

Cattle over 5 years 

Total 



5, .')59 

7,744 
fi, 047 
10, 850 
11,924 



40, 624 



675 
2,129 
1,949 
4,644 
6,724 



12.1 
27.5 
38.6 
44.9 
48.0 



15, 121 



37.2 



This table shows that, in a countr^^ where from 45 to 48 per cent of 
the adult cattle are tuberculous, 12.1 per cent of the calves are aft'ected 
by the time they are six months old. If 2 per cent of these calves 



36 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

have congenital tuberculosis it follows that more tlian 10 per cent of 
them contract the disease from the milk which they drink ov from the 
infected stables in which they are kept. During- the second half year 
of the life of the animals an additional 15 per cent become infected. 
Probabl}^ the greater part of the infections during the first year result 
from contaminated food. These statistics, therefore, show the impor- 
tant role played by infected milk as a disseminator of tubercular disease. 
Phelps,^* of the Storr^s (Conn.) Experiment Station, reports the 
results of experiments made there in feeding to calves the milk of 
tuberculous cows: 

During the greater part of the four years that 4 tuberculous cows were at the sta- 
tion the milk of some or all of them was fed to calves. The results of the tirst two 
years' feeding show that, while the milk of each of the 4 cows was fed to several 
calves in periods ranging from three months to one year and four months, in no case 
was there any indication of disease in the calves during the feeding period. The 
calves were ke]it with the cows nearly two years. One of these calves responded to 
the tuberculin test alwut five months after the feeding period of sixteen months was 
ended, and was found upon post-mortem examination to be very slightly diseased. 

Two calves, the offspring of tuberculous cows, were selected for a comparison of 
the infectiousness of pasteurized and raw milk. About half of the milk of 1 cow 
was heated to about 170° F. and fed to her offspring, and the balance of the milk in 
its natural state was fed to the offspring of the other tuberculous cow. The calves 
were isolated from the cows. Neither of the calves responded to a tuberculin test 
made after a feeding period of about ten months. By a misunderstanding both of 
the calves were fed the unpasteurized milk of the cow for a period of three weeks 
(following the tuberculin test) , after which they were turned out to pasture for about 
live months. Three weeks after being returned to the stable with the cows the calf 
which had been fed the pasteurized milk (except for three weeks) responded to the 
tuberculin test, while the other calf failed to respond until five months later. 

Two other calves were fed the milk of their dams from August and September, 
1898, until the next June. At the end of ten months' feeding in one case and nine 
and one-half in the other neither of the calves responded to the test. One calf was 
at pasture from June 24 to November 13, while the other remained in the stable with 
the cows. Both responded to the test on December 2 following, three weeks after 
one of the calves was returned from the joasture. 

Two more calves were fed the milk of the 2 other cows. Both had tuberculous 
mothers. One was kept in the stable with the cows, and after being fed the milk of 
cow No. 1344 for a period of ten weeks responded to the tuberculin test. The other 
was fed the milk of its dam (No. 1343) while isolated in a room in another part of 
the barn. After a feeding period of nearly three months this calf responded to the 
tuberculin test. 

Three other I'alves from nontuberculous cows were selected early in ]\Iay, 1900, 
and placed in a small pasture near the station barn. Calf L was fed the milk of 
No. 1337, calf M the milk of No. 1341, and calf N the milk of No. 1343. All prac- 
ticable precautions were taken to prevent the transmission of the disease in any way 
except by the milk. The calves were tested May 24-25, about three weeks after the 
feeding began, and again September 28-29, after having been fed over four and one- 
half months. None of the calves responded to either test. The calves were not fed 
milk after the September test but were kept isolated from the cows. Calf M died 
November 29, and an examination b}' the station veterinarian revealed a congested 
condition of the stomach, kidney, and bladder, indicating some form of poisoning. 
An examination of the lungs also demonstrated the existence of tuberculosis, there 
being a tuberculous nodule in the right lung, calcified, and the mediastinal lym- 
phatic being tuberculous. The two remaining calves failed to respond to a tuber- 
culin test in February, 1901, and in May were sent to pasture with some other stock. 

Thus in the first feeding test 1 calf out of several became tulierculous, and in the 
four succeeding tests 7 out of 9 eventually became tubert-ulous. Tiie 2 which did 
not respond to the test may or may not have been diseased. The uncertainty of 
depending upon repeated tuberculin tests in such cases is shown by the last- 
mentioned experiment, in which no tuberculosis would have been found had it not 
been for the accidental death of one of the calves. Some of these calves may have 
been infected through cohabitation, but in any case the large proportion of infection 
shows the danger of having tuberculous cows in a herd. 



MATERIAL FACTS CONCERNHSTG TUBERCULOSIS. 87 

SPKEAT) OF TUBERCULOSIS FROM DISEASED TO HEALTHY CATTLE. 

The rapid and widespread dissemination of the disease by the sale of 
l)reedino- stock from tubercular herds has been pointed out by Russell 
and Hasting-s.^* 

AVhere the disease establishes itself in herds that are sold for breeding purposes 
the danger is much increased, for animals from such sources are nmch more apt to 
be widely disseminated, since they generally serve as a foundation for the breeding 
up of common stock. The State of Wisconsin, as well as other Northwestern States, 
has suffered in this regard very severely from some of its finest breeding herds. One 
herd in particular in tliis State has had anything but an enviable record in this mat- 
ter, for it has been determined that tuberculosis has broken out in at least 16 herds 
to which members of this original herd were sold. While it can not be proved that the 
origin of the disease in each of these 16 cases could be traceiltothe animals originally 
purchased, yet it is noteworthy that in a considerable number of cases the first animals 
to show evident symptoms of the disease were those that were introduced from this 
badly diseased herd. Not only were a number of fine herds in Wisconsin infected 
from this source, but the contagion was also spread, in a number of cases, to Minne- 
sota and Iowa. 

Schroedei- and Cotton^'' have made experiments to test the rapidity 
with which tuberculosis spreads in a stable from diseased to healthy 
cattle. 

Seven healthy cattle and 3 tubercular cows were confined in a stable containing 
10 box stalls, which were separated by solid 2-inch plank partitions 6 feet high. 
Five of the healthy cattle and the 3 tuljerculous cows occupied different stalls 
each day, in a rotation which exposed eacii of the healthy cattle equally to the 3 dis- 
eased cows. Two of the healthy cattle occupied stalls near the center of the stable 
and were at no time allowed to enter other stalls or to come into closer contact with 
any of the other cattle. 

Two and one-half months after the beginning of the experiment 1 of the 3 tuljer- 
culous cows was removed from the stable, and 2 other and more severely affected 
cows were introduced. One of these tuberculous cows died after it had been in the 
stable two months, and was found to l)e affected with generalized tuberculosis, but 
without disease of the udder or lymph glands associated with or near the udder. 
All of the exposed cattle were tested with tuberculin at the beginning of the experi- 
ment and found to be free from tuljerculosis. 

The experiment l)egan January 27, 1903, and the exposed cattle were tested with 
tuberculin on June 30 following. The two animals which had been confined to 
their stalls were a yearling bull, which reacted to the last test, and a 6-year-old 
cow, which did not react. Both animals were found tu1)erculous when killed and 
examined August 3, 1903. In the bull the posterior mediastinal glands were slightly 
enlarged and contained numerous small recent foci of tuberculosis. The anterior 
mediastinal glands were greatly enlarged and filled with foci of tubercular material, 
and the bronchial glands contained several small foci of recent tubercular disease. 
The cow also was diseased, having several of the mediastinal glands greatly enlarged 
and thickly sprinkled with small tul)ercular nodules, recent in character, and, in 
addition, several small recent areas of tuberctilar disease scattered through the lung. 

Two heifers, 1 six months old and 1 eighteen months old, both in good condition, 
were made to occupy a different stall each day in order that they might ])e exposed 
equally to each of the tuberculous cows. When tested with tuberculin on June 30 
both reacted. Post-mortem examination of the younger animal showed the left 
principal lobe of the lung adherent to the chest wall and near the adhesion a tul)er- 
culous nodule in the lung tissue about 1 inch in diameter. The anterior and posterior 
mediastinal glands, the bronchial glands, and the lymph glands about the root of 
the tongue were greatly enlarged and either entirely tubercular or thickly sprinkled 
with minute tul>ercular foci. Several of the mesenteric lymph glands were con- 
verted to the extent of half of their substance into tubercular material, and a num- 
ber of other mesenteric glands were affected, as were also the glands at the brim of 
the pelvis in the abdominal cavity. The lesions were all of comparatively recent 
origin. The older heifer had one small fopus of tubercular disease in the left prin- 
cipal lobe of the lung, and sprinkled over various portions of the pulmonary pleura 
of the right principal lobe of the lung were numerous tubercles with corresponding 
tubercles on the costal pleura. The pulmonary surface of the diaphragm was 



88 TUBERCULOSIS OF THE FOOD-PRODUCHSTG ANIMALS. 

Hprinkled with numerous small tubercles, and the various lobes of the lung were 
adherent to each other and to the diaphragm by means of tissue containing many 
tubercles. The appearances were typical of pearl disease in cattle. 

Three other cattle were exposed in the same manner as the 2 just described, but 
these had previously been given intravenous injections of dead or living tubercle 
cultures. One of these, a bull calf six months old, had 20 c. c. of dead culture of 
human origin injected into the right jugular July 12, 1902, and at the beginning of 
this experiment was in good condition and gave no reaction. When tested June 30, 
1903, it reacted, arid on post-mortem examination tubercular deposits were found in 
the anterior and posterior mediastinal glands, while the lym]ih glands back of the 
jiharynx were five times their usual size and completely tuberculous. There were 
also a number of recent tubercular foci in the liver. The second animal, a heifer 
calf al)Out four and one-half months old, had received in the right jugular 20 c. c. of 
dead bovine tubercle culture July 19, 1902. This animal was also in good condition 
and failed to react at the beginning of the present experiment. When tested June 
30, 1903, she gave a marked reaction. She was slaughtered and examined August 

5, 1903, at which time there was found tuberculosis of the mediastinal and bronchial 
glands and of one mesenteric gland. The third animal of this group was a cow 
about two years old. This animal had received injections of 10 c. c. each of moder- 
ately virulent human tubercle culture into the right jugular vein on July 19, August 

6, August 20, September 20, and October 7, 1902. When admitted into this experi- 
ment, January 27, 1903, she looked thin and unthrifty, but failed to react. She 
also failed to react to the test of June 30, 1903. Killed and examined, August 6, 
1903, the entire lung was found to be sprinkled with minute white nodules, having 
an appearance similar to that observed on several occasions after the injection of 
human tubercle into the veins of cattle. No tuberculous lesions were found in other 
parts of the body, and the disease in this animal was undoubtly caused by the 
injections of the cultures of human bacilli. 

The rapidity with which tuberculosis spreads in stables occupied b}" 
ttiberculous cattle is shown with particular emphasis b}" the two cattle 
which became tuberculous without actual contact with the tuberculous 
cows and while standing in stalls which were separated from the other 
stalls b}^ solid partitions 6 feet high. The distribution of the lesions 
indicate that the germs of tuberculosis in stable infection are more 
commonly respired than ingested with food. This experiment clearly 
shows that cattle can not be protected from tuberculosis when in the 
stables with tuberculous cattle, even when each animal is carefully 
restricted to its own individual stall. 

THE EFFECT OF INSANITARY CONDITIONS. 

The ideal conditions for health and for resistance to the tul)ercul6sis 
contagion are life in the open air and an abundant supph^ of nutritious 
food. The greater the departure made from these ideal conditions, 
the more is the development of tuberculosis favored. At the same 
time it should be remembered that this disease will not appear in an 
animal unless the tubercle bacillus has gained entrance to its tissues, 
and this bacillus can not originate in a stable, no matter how insanitary 
its conditions may be. The tubercle ])acillus, like other forms of liv- 
ing things, must come from a preexisting germ of the same species; 
and as it grows only in the body of an animal, it must be transported 
in some manner from a diseased animal to a healthy one before the 
latter can contract the disease. These are foundation principles which 
are thoroughly established and which must be borne in mind in han- 
dling animals for the prevention or the suppression of tuberculosis. 



MATERIAL FACTS CONCERlSriNG TUBERCULOSIS. 39 

Life ill the open air is not always sufficient to prevent infection with 
tuberculosis or to cure animals that are already ati'ectcd by it, but its 
influence is favorable and reduces the chances of infection to the small- 
est proportion, while at the same time it places the diseased animal 
under the best conditions for its recovery. In most stables the condi- 
tions of life are radicall}^ diflerent from what they are in the open air. 
It is only necessarj^ to make the most casual inspection of the ordinary 
stable to assure oneself that the conditions of life there are unfavor- 
able in the extreme. 

Yentilation. — Most stables have no provision for ventilation. Any 
air which enters them must come through the doors or the walls of the 
building.s; either there are drafts of air upon the animals, favoring 
the production of colds and catarrhs, or there is an insufficient supply 
of oxygen. The circulation of pure air in a stable furnishes an abun- 
dant supply of oxygen, which increases the resisting powers of the 
animal, and it also serves to carr}^ away dust and other impurities 
whicli may l)e floating in the atmosphere of the stable. Where there 
is no ventilation disease germs carried into a stable are likel}" to remain 
there until they infect the animals. Where there is little ventilation 
stables arc almost always damp, and such dampness favors the preser- 
vation of the bacilli and tends to the production of catarrh in the air 
tubes of the animals, which is a condition favorable for the lodgment 
of these germs. Tuberculosis is most frequent w4th people, as well as 
with animals, who are crowded together in small and poorly ventilated 
quarters. An abundant supply of fresh air in the stable acts favorably 
in several waj^s: First, it is a means of supplying the animals with a 
proper amount of oxygen for carrying on the functions of their bodies; 
second, the circulating air carries away the carbon dioxide and the 
moisture given off from the animals' bodies, and leaves the stables dry 
and healthful; third, the air currents also carry away bacteria of all 
kinds whicli may be floating in the atmosphere of the stable, and in 
that way they reduce the chances of infection; and, fourth, fresh air 
and dryness are unfavorable conditions for the preservation of 1)acteria, 
and, consequently, well- ventilated stables are not so easily infected as 
others, and the infection dies out more readily in them. 

Llglit. — It is just as desirable that there should be ample provision 
to let light into a stable as that there should be ventilation. The 
direct rays of the sun are of especial value for destroying tubercle 
bacilli and for increasing the resistance of the animals to their attacks. 
In addition to this the sun's rays aid in drying and disinfecting the 
stable. Light is also necessary to enable those who care for the stable 
to see the dust and tilth and to put it into proper sanitar}" condition. 
Dark stables are almost universally dirty, damp, and uiihealthful. 

Pearson and Ravenel' say with reference to this subject that — 

It has been shown by Migneco, Straus, and others that tubercle bacilli are destroj^ed 
by lio;ht in a time that is in proportion to the intensity of the light and inversely as 
the thickness of their protective coating. In Migneco's experiments sputum con- 



40 TUBERCULOSIS OF THE FOOD-PKODUCING ANIMALS. 

taining many bacilli were spread out on linen or cotton cloth and then exposed to 
sunlight. Subseciuently the cloth was washed in sterile water and the wasli water 
was injectetl into the peritoneal cavities of experimental animals. The virulence of 
the germs was greatly reduced in from ten to fifteen hours and when the layer was 
not too thick they were c-omjiletely destroyed in twenty-four to thirty hours. 

Sunlight has a decided effect on the chemical processes that take place in living 
tissues. In the case of plants this is very marked. Dammann states that animals 
expire smaller quantities of carbon dioxide at night than during the day. Accord- 
ing to the experiments of Platin, which were made on rabbits, the increase in oxygen 
consumption and in carbon dioxide excretion under tlie intluence of light is from 
13 to 14 per cent. Dammann calls attention to the fact that this result is in full 
accord with the general experience that animals fatten best in dark stables, and it is 
also noticed that animals kept in dark places for long periods become sluggish. The 
pallor that is characteristic of miners, stokers on ocean vessels, and prisoners is also 
due to the absence of light. In darkness there appears to be a checking of the 
metabolism and tissue change, an indolence of excretory functions. 

De Renzi has made some experiments to deterniine the effect of direct sunlight on 
tubercular i)rocesses. He inoculated 8 guinea pigs with tuberculous sputum and 
afterwards placed half of them in a glass box and the others in a wooden box. Both 
boxes were ventilated from below and were placed in the sun. The animals in the 
wooden ))ox died on an average of twenty-seven days after the inoculation, while 
those in the glass box lived an average of fiftj'-seven days. 

Similar experiments have been made in the laboratory of the Pennsylvania live 
stock sanitary board, and it has been shown that light jirolongs the life of a tubercular 
animal. 

Cleanlmess. — A stable must be clean in order to be sanitary. 
Cleanliness is the first principle of sanitation, and it must be contin- 
uall}^ l^ept in view. Not only must the tilth on the surface of the 
floors be removed, but there nuist be no channels by which it can 
gather between or beneath the flooring to ferment, putrify, and 
pollute the atmosphere with noxious gases. The dust which gathers 
upon the walls is often even more objectionable than the filth upon 
the floors. In infected stables the dust is certain to contain tubercle 
bacilli, and these are in a condition to be easilv floated in the atmos- 
phere and breathed into the animals' lungs. A stable to be sanitar}^ 
should be so constructed that the floors, walls, and ceilings may be 
thoroughly cleaned and disinfected. It should be free from cracks, 
inaccessible ledges, and corners, and from decayed wood, all of which 
may harbor contagion. The first thing is to have the stable so 
constructed that it is possible to clean it thoroughly, and the second 
thing is to see that it is frequently cleaned and that it is occasional!}" 
disinfected. If there are tuberculous cows in a herd, the feed boxes 
and mangers soiled with the saliva of the diseased animals are the 
most dangerous parts of the staljle. Next to these are the parts 
covered with thin layers of manure, which becomes dry and pulverized 
and is carried into the air as dust; and not less dangerous is the dust 
which has accumulated on the walls and in ever}^ part of the stable 
where it can lodge. In cleaning such a stable the walls and ceilings 
should be swept and washed as Avell as the floors, and the whole 
interior shoidd be drenched with the disinfecting liquid. 

To be in a sanitary condition a stable must, therefore, be well ven- 
tilated, l)ut free from strong currents of air; it must be light and 
permit the entrance of the sun's rays during at least a part of the 



MATERIAL FACTS OONCERNHSTG TUBERCULOSIS. 41 

day; it must be dry, with no stagnant water standing under or near 
it; and, tinall}', it must be clean, not only as regards the accumulations 
of manure in the gutters, but as to the less noticeable contaminations 
of the floors and walls. 

If these conditions are realized, a long step will haye been taken in 
the struggle against tuberculosis; the disease will not spread so rap- 
idly in such a stable as in the ordinary kind, and it will be far more 
easy to eradicate the contagion from it. But no matter how perfect 
the stable or how unimpeachal)Ie the condition in which it is main- 
tained, there is still danger of the disease spreading if a tuberculous 
cow is brought into the herd, and if a number of cows haye become 
afi'ected tliese animals must be discovered and removed before the dis- 
ease can be suppressed. Tuberculosis can not })e successfully combated 
by sanitary conditions alone. 

Dr. Leonard Pearson*" has made interesting investigations ])earing 
upon the effect of bad stabling conditions in favoring the spread of 
tuberculosis among cows. 

For the purpose of the investigation 2 lierds were estaliHshecl of 6 cows each. 
Four in each herd were healthy and 2 in each herd were tul^ercular. One lierd was 
kept in a roomy, light, clean, and well-ventilated stable. The stalls and partitions 
between the mangers in this stable were so constructed that the cows were kept 
apart from each otlier. 

The other stable was small, close, poorly ventilated, rather dark, and not especially 
clean. The cows here were not separated l)y stall i)aititions, and they were all fed 
from the Hoor of the passageway in front of their stalls. 

This experiment continued for five hundred and thirteen days, or about seventeen 
months, and at the close it was found that 2 of the originally healthy animals kept 
in the large light stable had contracted tuberculosis, and the other 2 of the originally 
healthy cows continued sound. Of the 4 originally healthy cows in the small dark 
stable all had contracted tuberculosis. The progress of the disease in each infected 
animal in the dark stable was greater than in the infected animals in the light airy 
sta1)le. 

THE DETECTION OF TUBERCULOSIS. 

The detection of tuberculosis in any other way than by the tubercu- 
lin test is often dithcult or impossible during the life of the animal. 
In the case of a herd of cattle we have three sources of information — 
the symptoms brought out by a physical examination of each of the 
individual animals, the tuberculin test, and the examination of the car- 
casses of such animals from the herd as die of disease or are slaughtered. 
Each of these sources of information is of great value, and none of 
them should be neglected in case there is any reason to suspect the 
existence of the disease. 

PHYSICAL EXAMINATION. 

The inspection of a herd of cattle affected with tuberculosis fre- 
quently reveals evidence strongly indicative of the presence of the 
disease. Some of the animals may be emaciated, the skin tensely 
drawn over the bones, the hair standing on end, rough, and lusterless. 
There is an undue amount of coughing in the morning when the ani- 
mals are fed, when they are driven out of the stable into the cold 



42 TUBEECULOSIS OF THE FOOD-PKODUCIT^G ANIMALS. 

air, after drinkino* cold water, or when they are made to take rather 
violent exercise. The lymphatic glands located about the throat, in 
front of the shoulder, or in the tiank may be enlarged. If the his- 
tory of the herd shows that occasionally an animal lost iiesh, yielded 
a decreased quantity of milk, and gradually pined awa}^ until it 
died or it became necessar}" to kill it, tuberculosis should be suspected. 

In examining the individual animals the object is to learn the con- 
dition of the organs most frequently the seat of tubercular disease. 
As the lungs are affected in from 60 to 75 per cent of the cases, these 
organs should receive careful attention. With tuberculosis of the 
lungs the most prominent symptom is a cough; this is persistent, 
short, dr}^, strong, and often high in pitch, almost whistling. As the 
disease advances the cough is more prolonged, violent, convulsive, and 
may be accompanied by protrusion of the tongue. Auscultation re- 
veals various modified and abnormal sounds in the lungs. There may 
be friction sounds, the result of disease of the pleura, increased respi- 
ratory murmur from bronchial irritation, loss of respirator}^ murmur 
from large tul)ercular deposits or adhesions, mucus rales from the 
inspired air being- drawn through collections of mucus in the air 
tubes, and whistling sounds from thickening of the walls of the bron- 
chial tubes. Percussion over the chest walls may in some cases show 
al)normal resonance from the tubercular deposits causing portions of 
the lungs to recede from the ribs, but in a larger number of cases 
there are areas of dullness corresponding to tubercular masses. In 
many cases with severe lesions of the lungs no satisfactory evidence 
can he obtained by either auscultation or percussion. 

The mediastinal glands are situated between the lobes of the lungs 
and rest upon the esophagus. Very often in tuberculosis they are dis- 
eased and enormously enlarged, and in such cases the}" press upon the 
esophagus and cause digestive disturbance, more particularl}^ chronic 
bloating, which may appear regularly soon after eating, no matter what 
the character or the quantity of the food taken. Habitual bloating, 
when the food is of good quality and taken in proper amount, and when 
there is no other evidence of disease of the digestive organs, is consid- 
ered strongl}/^ indicative of tuberculosis with enlargement of these glands. 

In tuberculosis of the stomach and intestines digestion is more or 
less interfered with, the ap]:>etite becomes poor or irregular, and 
there is frequently diarrhea, or diarrhea alternated with constipation. 
There may also be liloating and colicky pains. 

With tuberculosis of the uterus and ovaries, and sometimes with 
peritoneal tuberculosis, the cow remains almost constanth" in heat, but 
is often sterile. W^hen the postpharyngeal glands are affected there 
is interference with the breathing, which becomes harsh and loud; 
there may also be difficult}^ in swallowing. It is sometimes possible 
to feel the enlarged glands by placing one hand on each side of the 



MATERIAL FACTS COlSrCERNING TUBERCULOSIS. 43 

throat and then pressing- witli both hands over the region of the throat 
above the lar3nix. 

In case tul)ercles form in the brain or spinal cord the symptoms 
var}^ somewhat according" to the part affected. The tirst signs are 
depression, soon followed b}^ stiffness and unsteadiness of the gait. 
The animal lies down a great deal and rises to its feet with difh- 
culty. As the disease advances there may be cramps of the muscles 
of the neck and local paralysis, causing difficulty of swallowing. The 
food is retained a long- time in the mouth and is finally dropped into 
the manger. Sometimes tlie sj^mptoms are those of acute meningitis, 
when the animal is nervous, excitable, frenzied, and may have con- 
vulsions and coma. Usuall}" the spinal cord and brain are affected at 
the same time, the effect of disease of the cord being to make locomo- 
tion more and moi'e difficult and to bring about paraplegia and paraly- 
sis of the posterior extremities. 

With tuberculosis of the tongue the lesions may be localized or 
disseminated throughout the organ. In the former case the tongue 
preserves its mobility, but on examination a swelling ma}^ be detected 
in some part of it, which is hard and eml)edded in the tissue. As the 
tubercular process advances an ulcer forms on the upper surface of 
the tongue over the swelling-, which is covered with a firm yellowish 
exudate. When the tubercular deposit is diffused through the org-an 
the tongue loses its mobility, becomes hard, and has an appearance 
similar to the "wooden tongue," which occurs in actinomycosis. The 
diagnosis is made bv a microscopical examination of the affected tissues. 

Tubercular inflammation of the stille joint, and less frequently of other 
joints, may occur during- the progress of the disease. The affected 
joint is swollen, warm, and very painful. There is great lameness 
and the animal is hardly able to put its foot to the ground. Such 
inflanmiations of the joints in cattle and hogs should lead to the suspicion 
of tuberculosis. 

Sometimes the tuberculous process is localized in the trachea and 
larynx, and this may occur either in connection with lesions of other 
organs or independent of them. The respiration is harsh and loud and 
accompanied by a mucus rale or g-urgling sound caused b}^ the accumu- 
lation of mucus in the trachea. In such cases there is a frequent and trou- 
blesome cough which is easil}^ excited by "pulling on the tongue or by 
slight pressure upon the larynx. The animal stands with the nose 
raised, the head extended upon the neck, and avoids lateral movements 
of the head and neck on account of the tenderness of the affected region. 

The diagnosis of tuberculosis of the udder is a matter of extreme 
importance, on account of the danger from infected milk. Great 
attention has, therefore, been given to this subject by many investi- 
gators. A recent and very minute study of mammary tuberculosis 
has been made by Ostertag, Breidert, Kaesewurm, and Krautstrunk,^'' 



44 TUBEECULOSIS OF THE FOOD-PRODUCING ANIMALS. 

and we are now able to speak with some contidence both as to the 
methods of examination and the sj-mptoms which are nsually found. 
Tuberculosis of the udder is indicated b}^ swelling- and hardening of 
one or more quarters. It usually begins in one of the posterior quar- 
ters and takes a chronic course. The swelling causes the teats of one- 
half of the udder to assume a parallel or converging direction, instead 
of diverging from one another. A health}^ quarter feels soft or mod- 
erately lirm throughout; in milch cows the normal elastic tissue often 
contains symmetrical, Him masses of var^nng size formed hy the 
lobules of the gland. A tul)erculous <|uarter feels irregular from the 
beginning of the disease. Certain portions, especially toward the back 
of the udder and over the milk cisterns, are firm, stiff, or as hard as 
wood. The firm parts form more or less sharply margined lobules, dis- 
tinct from the normal elastic tissue. The tuberculous swellings in- 
crease in circumference, and in time their surface becomes nodulated. 

When the udder is distended the tuberculous swellings are often 
difficult to detect, but in the relaxed condition of the organ after milking 
this difficulty disappears. The swellings are painless and of the same 
temperature as their surroundings. The milk of the diseased quarter 
ma}^ remain apparently normal for weeks, ]>ut as the tul^erculous pro- 
cess extends and destroys the secreting tissue it changes in appearance, 
becomes thin, flocculent, and iinall}" water3\ At this time it often 
exhibits an alkaline reaction instead of the normal neutral reaction. 

In exceptional cases tuberculosis of the udder may commence with 
acute inflannnation, or may for a time assume an acute course. The 
lymphatic glands of the diseased quarter or half are alwaj^s swollen. 
Their condition can most conveniently be examined b}" thrusting the 
skin covering the side of the diseased hind quarter upward, toward 
the flank, with the index, middle, or ring linger, and palpating the 
posterior and lateral aspects of the glands in question. When diseased, 
the glands ai-e found to be enlarged in all directions; sometimes their 
surface is nodulated. 

Disease simulating tuberculosis of the udder may be produced by 
chronic infection with streptococci or with actinomyces. In the 
chronic inflannnation due to streptococci the lymph glands are greatly 
enlarged but are not nodulated. In actinomycosis of the udder the 
lymph glands are seldom much enlarged. 

The clinical diagnosis of tuberculosis of the udder ma}" be regarded 
as assured when one quarter of the udder and its attached lymph 
glands exhibit firm, hard, nodidated swellings without signs of inflam- 
mation. When the ipuirter and attached lymph glands exhibit only 
firm, hard swellings, without nodulation, the diagnosis is somewhat 
doubtful. Suspicion, however, will be increased if the milk from the 
suspected quarter is of apparently normal constitution, or appears, 
from the history, to have been of normal constitution at the com- 



MATEEIAL FACTS CONCERNING TUBERCULOSIS. 45 

mencement of the disease. The probability of tuberculosis is again 
increased by the existence of an}' other clinical indications of the dis- 
ease, such as (1) general falling off in condition; (2) continued fever 
without apparent acute disease; (3) painless nodulated swellings of the 
phar^nigeal, prescapnlar, or precrural lymphatic glands without sjaiip- 
toms of inflammation; (4) frequent, spontaneous, weak cough, and 
pneumonic rsiles without apparent acute inflammation; (5) frequently 
recurring tympanites without apparent cause; (6) frequent oestrum 
and nmcopurulent discharge from the vagina; (7) reaction to the 
tuberculin test. In rare cases symptoms of tuberculosis of the brain 
and tuberculosis of the vagina may lend additional weight to the sus- 
picion of tuberculosis of the udder. 

Portions of the prescapidar and precrural glands may be removed 
without danger. Removal of portions of the mammary l3miph glands 
is somewhat difficult on account of the deeper position of these parts, 
but is also without danger. Macroscopic examination of such frag- 
ments is often sufficient to reveal the tuberculous nature of the disease. 

As a rule, bacteriological examination is indispensable for the con- 
clusive diagnosis of tuberculosis of the udder. Of the various forms 
of examination undertaken with this ol)iect, inoculation of guinea pigs 
with suspected milk is the most reliable. One cubic centimeter of 
milk as withdrawn is sufficient. The milk should be injected into the 
muscular substance of the inner and posterior surface of the hind limb. 
This is as reliable as intraperitoneal injection, which was formerly the 
most widel}^ employed, and was regarded by Rabinowitsch as the most 
conclusive, while it has the advantage of being much speedier. The 
experimental animal can be killed for further examination as soon as 
the lymph glands near the^point of inoculation appear lirm, hard, pain- 
less, and enlarged to the size of a small pea. This often occurs within 
ten days of inoculation; but shoidd the lymphatic glands not become 
diseased, the experimental animals are killed six weeks after inocula- 
tion. The discovery of tubercle bacilli in the enlarged lymph glands 
or internal organs confirms the diagnosis. Intranuiscular injection 
obviates sources of error due to the pseudotuberculous changes which 
so often follow intraperitoneal injection of milk accidentally contain- 
ing acid-fast pseudotubercle bacilli. The entrance of acid-fast bacilli 
(which, by the waj'^, can usually be recognized as such on account of 
their shape) can l)e avoided if, before withdrawing the milk, the udder 
be washed with soap and water, cleansed with 50 per cent alcohol, and 
rubbed dry with sterilized wadding. The first 10 c. c. at least of the 
milk should be thrown away. Finally, the intramuscular method has 
the great practical advantage over the intraperitoneal that much fewer 
experimental animals die from intercurrent diseases. 

Examination of the milk by means of smear preparations and the 
bacterioscopic examination of harpooned fragments of the tissue of 



46 TUBERCULOSIS OF THE FOOD-PRODUCHSTG ANIMALS. 

the udder are uncertain. Despite the exi.stence of the disease, a con- 
siderable number of such tests may fail. This conclusion, at least 
as regards smear preparations, is in harmon}' with the reports of 
Rabinowitsch and Miiller. The last method of examination is only 
conclusive when it yields a positive result. Nevertheless, as stated l)y 
Bang and Midler, it is valuable for the rapid diagnosis of advanced 
tuberculosis of the udder. In certain exceptional cases harpooning 
of the udder may prove more reliable than inoculation. For bac- 
teriological examination the milk should be passed through a cen- 
trifugal separator and the precipitate used. 

Harpooning necessitates casting' the animal. By carefully disin- 
fecting the skin and using sterilized instruments, the operation is 
rendered harmless even if repeated several times. The skin and the 
fascia of the udder are first divided, the suspected portion of the 
udder grasped with the hand, the harpoon introduced into the sup- 
posed diseased part, rotated slightly, and rapidly withdrawn. " A 
small fragment of tissue is sufficient, provided a tubercle can be rec- 
ognized by macroscopic or microscopic examination. Harpooning 
may be resorted to when inoculation has failed to contirm an other- 
wise strong suspicion of tuberculosis, or when the milk has ceased to 
be secreted and therefore can not be emploved. 

In advanced cases of tuberculosis of the udder the secretion from 
tlie diseased (juarter ma}^ be virulent even when diluted to the extent 
of 1 to 1,000,000,000. In incipient tuberculosis of the udder, and 
sometimes in advanced cases, the number of bacilli is ^•ery small and 
the virulence of the milk can be destroyed b}^ dilution to a greater 
degree than 1 to 1,000. 

In examining nasal, pharyngeal, and vaginal discharges for tubercle 
bacilli it must be borne in mind that these materials, like the feces, 
contain acid-fast pseudotubercle bacilli, and, therefore, that in doubtful 
cases the results must be checked b}^ inoculation experiments. 

With hogs the sjaiiptoms of tuberculosis brought out by physical 
examination are usually not clear. The principal symptoms are pro- 
gressive emaciation and irregular diarrhea, sometimes accompanied by 
a cough. In most cases the glands of the neck are affected, and fre- 
quentl}" their eidargement causes a very apparent swelling of the neck. 
Very often there is tuberculosis of a joint and consequent lameness. 
Animals showing these symptoms should be regarded as suspicious. 

THE TUBERCULIN TEST. 

Tul)erculin is a product of the growth of the tubercle bacillus. It 
is prepared by sterilizing, filtering, and concentrating the liquids in 
which the tu])ercle bacillus has been allowed to multiply in the labora- 
tory. This su))stance was first made and studied by Koch, and it was 
fomid that when injected into the tissues of a tuberculous animal it had 
the effect of causing a decided rise of temperature, while it had no such 



MATEEIAL FACTS CONCERNING TUBERCULOSIS. 47 

effect upon animals free from tuberculosis. The value of tuberculin 
for revealing the existence of tuberculosis was tested by many investi- 
gators during the years 1890 and 1891. The injection of this new drug- 
was at once recognized as a most remarkable and accurate method 
for the detection of tuberculosis, even in the earh^ stages and while 
the animal appeared to be in perfect health. Our knowledge of the 
tul)erculin test was built up through the most careful and thorough 
scientific experimentation and should be accepted as entirely reliable. 

In practice the tuberculin test is conducted by first taking the 
temperature of the animal to be tested, at intervals of about two 
hours, a sufficient num])er of times to establish the normal temperature 
of the body under the ordinary conditions of life. The proper dose 
of tuberculin is then injected under the skin with a hypodermic syringe. 
The point of inoculation is not essential, but the side of the neck is 
usually selected for convenience and because of the thinness of the 
skin of that region. The injection is })referably made late in the 
evening, and the temperature is taken every two hours the following 
day, beginning early in the morning and continuing until late in the 
evening. Do Schweinitz, in 1896, calculated the average temperature 
of about 1,()00 tul)erculous cows wh'icli were tested with tuberculin, 
and from this average it appears that in general the rise of tempera- 
ture begins from five and one-half to six hours after the tuberculin is 
injected, reaches its greatest height from the sixteenth to the twentieth 
hour, and then gradually declines, reaching the normal temperature 
again b}' the twenty-eighth hour. When a chart is made showing 
graphically this gradual rise and decline of the animal's temperature 
after it has been injected with tuberculin, we have what is called the 
tuberculin curve. 

In stud3dng the variations of temperature which followed the injec- 
tion of tul)erculin into healthy and tuberculous cattle it was found that 
in order to diagnose tuberculosis safely there should be a rise of tem- 
perature of not less than 2° F., also that the temperature should at its 
highest point reach about 104° F. To avoid errors it was found to be 
important that a full dose of tuberculin should be administered and 
that a reaction should be considered to have occurred only when the 
temperature remained elevated for several hours. 

Many of the supposed errors of diagnosis made from the tuberculin 
tests during the first years of its use were due to an insufficient search 
for the tuberculous lesion in the carcass of the slaughtered animal. 
Tuberculin proved to be a much more delicate test for the existence of 
tuberculosis in cattle than was at first appreciated, and it was not until 
the veterinarians learned that a single small tubercle in an obscure 
part of the body was enough to cause a reaction that they began making 
a sufficiently careful search to discover such a lesion in case of its exist- 
ence. It is now generally admitted that a reaction seldom, if ever, 



48 TUBERCULOSIS OF THE FOOD-PRODITCTNG ANIMALS. 

occurs without there being a tubercle somewhere in the animal's bodj^ 
The errors of diagnosis arise not with the animals which react, but 
with the tuberculous animals which fail to show a reaction. Nearly 
all the animals failing to react although ali'ected with tuberculosis may 
be grouped in two classes. The first of these classes consists of ani- 
mals in an advanced stage of the disease and in most of which the dis- 
ease may be recognized by physical examination. The second class 
consists of animals which have been injected with tuberculin one or 
more times and which have become insensible to it. 

Tuberculin is of inestimable value for ascertaining whether tuber- 
culosis exists in a herd of cattle at a period when it could not possibly 
be diagnosed by physical examination. For this purpose it is practi- 
cally infaili})le in its indications, since when the disease exists in a 
herd of any size some of the afiected animals are certain to show a 
reaction. There are very many cases on record where herds supposed 
by their owners to be free from disease were found by the tuberculin 
test to be seriously infected. The determination of the fact of the 
existence of tuberculosis in a herd is of the greatest importance, for 
it enables the owner to adopt at the earliest moment the measures 
which are needed for the control and eradication of the contagion. 
The animals which react to the test are certainl}' afiected, and those in 
the same herd which fail to react must be regarded as suspicious until 
they have been kept for several months after the last reacting animal 
has been removed and have undergone subsequent tests without 
reacting. 

The cows in a tuberculous herd which failed to react to the tuber- 
culin test should be submitted to careful physical examination, and 
those which are emaciated, or have abnormal sounds in their lungs, or 
are frequently in heat, or which cough or have digestive disturl^ances, 
should l)e regarded as probably afiected. The udder should also be 
examined with great care, and if hard, painless swellings are found in 
one or more quarters, and particularly if a hind quarter is afiected, 
the troulfie is probably caused by the tuberculosis bacillus. By this 
careful physical examination the cows in a more or less advanced stage 
of the disease which fail to react to the tuberculin test may be detected 
and measures taken to prevent the disease spreading from them. 

The second class of cases from which errors are liable to occur — that 
is, the animals which have been injected with tuberculin until they 
have lost their sensitiveness to it — are not likely to be found in a herd 
tested for the first time, unless new animals have recently been pur- 
chased. The first test of a herd with tuberculin combined with a 
physical examination of the individual animals may therefore be 
accepted as reliable in its indications, not only as to the existence of 
tuberculosis in the herd, but also as to the healthf ulness of the various 
animals composing the herd. 

With newly purchased animals and those about to be taken into the 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 49 

herd the case is different. A tuberculous animal may have been injected 
several times for the express purpose of putting it into a condition that 
will prevent its reacting- at the time of sale, or it maj^ have been 
injected a number of times in the ordinary course of procedure with a 
tuberculous herd. It is, therefore, unsafe toi)urchaso an animal from 
a tul)erculous herd, even if it fails to react when tested with tul)erculin. 
A single injection with tuberculin may })e sufficient to prevent an 
animal from reacting until a period of live or six months, or longer, 
has elapsed after the test was made; on the other hand, some animals 
react to every injection of tuberculin, even when there are but a few 
weeks' interval. 

The results of the test and examination of the extensively diseased 
herd of the Soldiers' Home, at Washington, by the Bureau of Animal 
Industry, are of especial interest because of the great care which was 
exercised to secure accuracy. In this herd 60 animals were tested 
with tuberculin and all of them were afterwards slaughtered and thor- 
oughly examined. The number of animals in the herd which reacted 
was 49, and the number which failed to react was 11. There was only 
1 animal among those which reacted in which no tut)er('ulous lesions 
were found. Of the 1 1 animals which failed to react, however, there 
were 5 that were found to be diseased. One of these which proved to 
have extensive tuberculosis had a high temperature (103.6° F.) the 
day before the test. This high temperature was sufficient reason for 
considering that the cow was probably tuberculous, and, moreover, 
the disease had been recognized from the external appearance of the 
animal and she had already been isolated from the herd. In the four 
remaining animals which were diseased but failed to react, the lesions 
were small and could not be detected by physical examination. This 
is an unusual proportion of such cases. The disease in three of these 
cows was apparently stationary, as the nodules were small and cal- 
careous. In the fourth cow the lesions were also small, and so far as 
could be determined were confined to the glands. 

In the careful 1}^ compiled statistics published by Voges^^ in 1897 it 
was shown that of T,32T animals tested, and of which the accuracy of 
the tests was determined by postmortem examinations, there were but 
204 errors of diagnosis, or 2.78 per cent. Pearson'^ states that in the 
work of the State live stock sanitary board of Pennsylvania post-mortem 
examinations were made on about 4,400 cattle which had reacted to the 
tuberculin test, and that among all these animals there were but 8 in 
which no lesions of tuberculosis were found. He adds with reference to 
these that we are not justitied in sa3'ing that tubercular lesions did not 
exist, for the reason that every portion of the carcass could not be 
examined; but it could only be said that they were not found. 

That cattle which once react to the tuberculin test may fail to react 
on subsequent tests is a fact which should be borne in mind. Obser- 

1881— No. 38—06 1 



50 



TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 



vations relative to this behavior of the animal bod}^ toward tuberculin 
have been made by many investigators. Some tests made at the Storrs 
Experiment Station are interesting examples of the failure of tubercu- 
lin under such conditions. 

The following table shows the record made at the Storrs station in 
retesting cows belonging to the herd of the Connecticut Agricultural 
College:'^*' 

Failure of tuberculin in case of repealed injections. 



Number of animal. 


Number 
of tests 

previous 
to first 

response. 


Date of first response. 


Date of test after first 
response. 


Date of second 

test after first 

response. 


1 


1 
2 
1 
1 
3 
2 

1 
3 
2 
3 
1 
3 
3 


December, 1898 

do 


May, 1899 a 




3 


do.'' 




4 


do 


do.o 


April, 1900. a 
Do.ft 


6 


do 


do.« 


6 


December, 1899 

December, 1898 

do 


April, 1900a 




7 


May, 1899 b 




8 


do.n 


Do. a 


9 


do 


do.'' 


Do.b 


10 


December, 1899 

May, 1899 


April, 1900O 




11 


November, 1900 b 

do.6 




12 


April, 1900 




14 


December, 1898 

do 


May, 1899" 




15 


do.& 




16 . 


do 


do.n 




17 


do 


do.'' 




18 


2 


do 


do.'' 












Total 


28 




IP (''8 
^>8 


4^2 









a Failed to react. '' Reacted. 

This table shows that 16 animals reacted, and that all but 2 of these 
had previously been injected from one to three times. From six 
months to a year after this lirst reaction these 16 animals were again 
injected, when 8 responded and 8 failed to respond. When eleven 
months more had elapsed 1 of these animals were tested for the second 
time after their first response, and of these 2 reacted and 2 failed to 
react. There were, therefore. 10 reactions and 10 failures to react to 
injections subsequent to the lirst reaction, or 50 per cent of failures. 

Phelps,"* of the same station, gives the following statement of the 
repeated testing of -1 tuberculous cows, taken for experimental pur- 
poses, during the four years they were kept at the station. 

January 26-27, 1897, first tuberculin test (at station), all reacted. 

April 26-27, 1S97, second tuljerculin test Nos. 1341 and 1344 reacted. 

July 30-31, 1S97, third tuberculin test, none of the cows reacted. 

September 27-28, 1897, fourth tuberculin test, none of the cows reacted. 

December 17-18, 1897, fifth tuberculin test, No. 1344 reacted. 

April 11-12, 1898, sixth tuberculin test. No. 1343 reacted. 

Deceml^er 22-23, 1898, seventh tuberculin test, none of the cows reacted. 

June 2-3, 1899, eightli tuberculin test, No. 1343 reacted. 

December 1-2, 1899, ninth tuberculin test, No. 1341 reacted. 

March 19-20, 1900, tenth tuberculin test, none of the cows reacted. 

September 28-29, 1900, eleventh tuberculin test. No. 1341 reacted. 

These cows, Nos. 1337, 1341, 1343, and 1344, had been tested before they came to 
the station by the State cattle commissioners, first in Marcli, 1896, when none of 
them reacted and they were pronounced healthy, and they probably were free from 
tuberculosis at that time; and second in October, 1896, when they reacted and were 
condemned as tuberculous. 



MATERIAL FACTS CONCEllNING TUBERCULOSIS. 51 

It was said bj^ Reg-ner'^^ at the International Veterinary Congress 
held in Budapest in 1905 that tuberculin is an invaluable and indispen- 
sable means for the extirpation of tuberculosis, but he who relies 
exclusivel}' upon it for ditferentiating- between tuberculous and non- 
tuberculous animals will sooner or later have bitter cause to regret it. 
Not only tuberculosis permitting of clinical diagnosis, but also cases 
where tuberculosis is present in a decided but not very high degree, 
usuall}^ not easily to be detected, ma}^ with individual animals elude the 
tuberculin test, and in a relatively short time, under favorable circum- 
stances, commit fearful ravages among the stock found free from reac- 
tion. Professor Svenssen, of Stockholm, has also proved bj^ means of 
a long series of experiments that tuberculin is somewhat uncertain for 
repeated tests upon animals once found to react. These facts render 
a clinical and bacterioscopic diagnosis imperatively necessary. Sup- 
pressive measures must especially be directed against the lung tuber- 
culosis, which is the most important factor of the dissemination of the 
pest among the cattle stalls. 

Taking into account recent publications on the subject, Eber'^^ 
fornuilates the following principles for judging the tuberculin reaction 
with cattle, which are based upon numerous observations of his own 
relative to the normal body temperature of cattle and its variations: 

.1. For young cattle up to 6 months old. — With young cattle up to 6 months old, if 
the temperature before the tuberculin injection is not found to exceed 40° C. ( 104° F. ) , 
all rises in temperature above 40° C. (104° F. ) are to be looked upon as reactions, 
provided that the difference between the highest temperature observed before the 
injection and the highest observed after it is at least 0.5° C. (0.9° F. ). 

B. For cattle more than 6 montJis old. — 1. Only such cattle are to be submitted to the 
tuberculin test as have a temperature not exceeding 39.5° C. (103.1° F. ) at the time 
of the injection. 

2. A rise of temperature to 39.5° C. (103.1° F. ) after the tuberculininjection is not 
in any case to be regarded as suspicious. 

3. With all cattle having temperatures not exceeding 39.5° C. (103.1° F. ) at the 
time of the tuberculin injection, every rise above 40° C. (104° F. ) is to be regarded 
as a reaction. 

4. Further, all rises of temperature above 39.5° C. (103.1° F. ) to 40° C. (104° F.) 
are to be considered reactions, when the total rise compared with the temperature 
before the injection is at least 1° C. (1.8° F. ). 

5. All rises of temperature above 39.5° C. (103.1° F. ) to 40° C. (104° F.) , when the 
total rise, compannl with the temperature before the injection, is less than 1° C. 
(1.8° F. ), should be regarded as doubtful, and the case judged on its merits. 

The decision as to which of these cases are to ))e considered as reactions and which 
as nonsuspicious is to be made according to the nature of the case. It has been 
found l)y experience that important aids to forming a decision are furnished by the 
total increase comi)ared witli the temperature before the injection — which with 
reacting animals as a rule should be 0.5° C. (0.9° F. ) at least — by the character of 
the temperature curve, and by an exact clinical examination, the necessity for which 
in doubtful cases is again emphasized. 

6. For all those cases in which the tuberculin test is simply to serve as a means of 
ascertaining the dissemination of tuberculosis in a stock of cattle, with the object of 
separating the suspected animals from those which are not susjiected, so as to carry 
on the suppression of tuljerculosis, it is sutticient, according to Ostertag, to regard 
all those cattle as suspected the interior body temperature of which exceeds 39.5° C. 
(103.1° F. ) after injection of the prescribed quantity of tuberculin — that being an 
increase of at least 0.5° C. (0.9° F.) above the highest temperature observed before 
the injection. 



52 TUBEECULOSIS OF THE FOOD-PRODUCING ANIMALS. 

It has often l)een alleged, g-enerall}^ by persons who have had no 
great amount of expei'ience in its use, that tuberculin has an injurious 
efi'ect upon the animals into which it is injected. This is contrary to 
the almost unanimous opinion of the scientific men who have studied 
its efiects and who have had most expei'ience in testing cattle with it. 
Tuberculin has little or no effect upon healthy cattle and its action 
upon tuberculous cattle is not serious. The writer has elsewhere (^') 
collected the opinions of many experts upon this subject and would 
refer to that article for details which can not be given here. 

A careful study of a great mass of literature on the subject has led 
to the conclusions which follow: 

1. The tuberculin test for tuberculosis is wonderfully accurate in 
its results, and if an animal responds it is certainly affected with the 
disease. 

2. The reaction to tuberculin is no indication of the extent of the 
disease in the reacting animal, and there is frequently a greater 
reaction in an animal with slight lesions than in another in which the 
disease is veA'j much more advanced. 

3. A small percentage of the cattle affected with tuberculosis fail 
for some reason to react to the tuberculin test. 

4. Tuberculin in the doses used for making the test has no injurious 
effect upon healthy cattle; if it has any effect at all it slightly increases 
their power to resist the tul)erculosis infection. 

5. The effect of tuberculin upon cattle already suffeiing from tuber- 
culosis is to cause a temporary fever with an increase of temperature 
of from 2° to 7'-' F., which usually lasts not longer than twenty-four 
hours. It is doubtful if tuberculin in this dose ever aggravates the 
tuberculous process in cattle, and there is some evidence that it may 
have a favorable effect. 

Tuberculin is not much used as a test for tuberculosis in the smaller 
animals, such as swine, ^' sheep, and poultry, because the normal varia- 
tion of temperature in these animals is so great that it is difficult to 
arrive at any accurate conclusions as to whether a reaction has occui'red. 

EXAMINATION OF THE CARCASS. 

The carcasses of all animals which die or are slaughtered from a herd 
should be carefully examined to determine whether they are affected 
with tuberculosis. This is an important means of learning as to the 
existence of the disease, and may give an early warning when its pres- 
ence has not been suspected. The examination of carcasses is espe- 
cially necessary with swine, since the tuberculin test is not generally 
used and is rather unsatisfactory with these animals. An examination 

« Experiments recently made by the Bureau of Animal Industry in testing hogs 
with tuberculin indit-ate that the application of tiie tes^t to these animals is i)racti- 
cable, and that tiie results are as reliable as with cattle, provided the hogs are kept 
very (juiet for some time before and throughout the test. 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 53 

of the carcasses of all aiiimals from a herd is an easy and accurate way 
of keeping informed as to the condition of health of that herd, and 
particularly as to the existence of any form of infection, or of any 
injurious parasites. 

The examination of a carcass for tuberculosis must not stop with an 
inspection of the lungs. The bronchial and mediastinal l^nnphatic- 
glands, which lie near the entrance of the bronchi into the lungs and 
along the course of the esophagus between the lungs, are more fre- 
quently affected than the lungs themselves. Of primary importance 
with swine are the glands of the neck, which are affected in a large 
proportion of the cases. In cattle the retropharyngeal, mesenteric, 
and portal glands should certainly be examined, as well as the liver, 
kidneys, and spleen. If the examination is made b}- a veterinarian, 
all of the accessible organs should be inspected. The yellowish nodules 
are easily seen in the principal organs of the body, and are also 
unmistakable in the Ij'mphatic glands if these bodies are opened with 
the knife. Any farmer or dairyman should with a little practice be 
able to recognize tubercular lesions in most cases, or should at least be 
able to tell if there is anything having the general appearance of tuber- 
culosis, and in case of doubt the affected organ may be saved and 
taken to a veterinarian for an expert opinion. 

IMMUNIZATION OF CATTLE AGAINST TUBERCULOSIS. 

The immunization of cattle against tuberculosis is a subject upon 
which investigators have been working for a number of years, with 
results that have inspired the hope that we shall haxe in the near 
future an additional means of combating the disease, and one that will 
greatly strengthen our present resources. The papers which have 
recently been published on this method of prevention, together with 
the discussions at the International Veterinary Congress held in Buda- 
pest in 10(»5, show that the ablest veterinarians in the world are conti- 
dentl}" expecting that a practical and safe plan of procedure will soon 
be developed. If this expectation is fulfilled the operations against 
tuberculosis will not only be materially simplified, ])ut the expense 
involved in the eradication of the disease and the loss falling upon the 
individual owners will he vastly reduced. 

A method of prevention which promises so much is deserving of 
ver}" careful consideration, even at this early stage of its development, 
for undoubtedly we shall soon be called upon to pass judgment as to 
its practicability. If it can be safely applied and is effective, it should 
be adopted and utilized as soon as it is perfected; but if, on the other 
hand, it is neither safe nor a satisfactory preventive, these facts should 
be made known as soon as possible. The value of the method can 
only be estimated when we have some knowledge of the investigations 
which have led up to it, and when we fully understand and appreciate 
the dangers which must be avoided. 



54 TUERBCULOSTS OF THE FOOD-PRODUCING ANIMALS. 

EARLY EXPERIMENTS. 

As lon^' ago as 188t) Dareiiibero" made experiments with a view to 
the production of immunit}' from tu])erculosis b}" inoculating guinea 
pigs and rabbits with sterilized cultures of the tubercle bacillus. The 
guinea pigs died and the rabbits were made sick; but some of the rab- 
bits after recoveiy and upon inoculation with virulent tuberculosis 
germs showed considerable resistance to the disease, as compared with 
similar animals which had not received the preventive treatment. 
This investigator also made experiments to test the effect of small 
doses of virus, and in one series of experiments he used medullas as 
a vaccinating material. His results, in some respects, were very 
striking, and appear to have made a profound impression upon him, 
for his paper which gave an account of the investigations was con- 
cluded with these words: 

From all these facts it follows that tuberculous virus is a poison which can be 
treated in a like mariner with mineral or organic poisons. Its toxicity may be 
increased or diminished alm(;st at will. On the other hand, one may augment the 
resistance of the organism against its disorganizing action. And I firmly believe 
that the day will come when in this ganmt of diverse virulences will be found the cor- 
rect note which will transform the virus into vaccine, which will fix with jirecision 
the attenuation infallibly conferring immunity. 

At the time this was written it seemed that the author was too san- 
guine and there were few who believed it possible to vaccinate success- 
fully against a disease which ran so slow a course and which was fatal 
in so large a proportion of cases. If imuuniity were developed in the 
animal body ])y the nndtiplication of the tuberculosis germs, why did 
not this immunity sliow itself during the progress of the naturally 
acquired disease, thus making it a disease of limited duration, ending 
in recovery? It appeared incredible that a bacillus which in so many 
cases advances slowly and insidiousl}" from one part of the animal 
body to another, often consuming years in its development to a degree 
where the life of the animal is destroyed, should by its normal l)iological 
processes confer a power of resistance upon the tissues of that animal 
body which would be effective against itself. 

In the same j^ear Grancher and Martin*- made pul)lic the results of 
a series of researches of great interest in this connection because they 
demonstrated that at that early date they had discovered a reliable 
method of attenuating the tubercle bacillus. These authors sa,y that 
they had applied themselves to the task of obtaining graduated viru- 
lences, even to the loss of virulence in the bacillus, and although the 
scale was in nowise mathematical it was sufficient to be utilized in 
about the same manner as were the dried marrows used in the method 
of Pasteur for the treatment of rabies. The}' designated under the 
name of virulence No. 1 the most virulent cultures in their series, 
which killed rabbits by intravenous injection in fifteen days or one 
month. Virulences Nos. 2, 3, -i, 5, 6, 7, 8, 9, and 10 were successively 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 55 

decreasing. The cultures from No. lo to No. 7, inclusive, resown in 
the culture apparatus, no longer developed, and were without effect 
upon rabbits. Virulences Nos. 2 and 3 were fatal, but at varying peri- 
ods according to the resistance of the animal. They believed that they 
had succeeded in giving to rabbits the power of a prolonged resist- 
ance against the most rapid and the most certain experimental tuber- 
culosis, and that they had also succeeded in conferring upon these 
animals an immunity against this same disease, the duration of which 
remained to be determined. 

Late in the year 1890 Trudeau *^ contributed a paper to the Medical 
Kecord in which he gave details of two series of experiments made 
with a view of obtaining immunity. In the first series preventive 
inoculation with the nonliving chemical products of the life processes 
of the tubercle bacillus failed to afford any protection against subse- 
quent infection with virulent living tubercle bacilli. In the second 
series preventive inoculation with an attenuated living germ, which 
was capable of producing in most cases only an indolent and localized 
tubercular process at the site of injection, failed to protect against 
subsequent inoculation with virulent tubercle bacilli. 

In May, 1894, Trudeau" read a paper before the Association of 
American Physicians on the production of immunity with avian bacilli. 
He concluded that rabbits which survived the subcutaneous inocula- 
tion of living cultures of the avian tubercle bacillus of gradually 
increasing virulence and in graded doses undoubtedl}^ acquired a cer- 
tain degree of immunity against subsequent eye inoculation with the 
mammalian cultures, which immunity had in some animals under his 
observation persisted for over a year without the slightest evidence 
of a relapse. He also found that while the rabbit, which is very much 
more susceptible to the avian than to the mammalian bacillus, may 
acquire a certain degree of immunity against the latter b}^ preventive 
inoculations of the former, the guinea pig, which can rarely and with 
great difficulty be killed by the avian micro])e, is in no way protected 
by this treatment. 

In December, 1894, De Schweinitz*'^ published an article entitled 
"The Attenuated Bacillus Tuberculosis; Its Use in Producing Immu- 
nity to Tuberculosis in Guinea Pigs.'' In this article he gave the re- 
sults of certain observations and experiments made by him in his work 
for the Bureau of Animal Industry, which were, briefly, as follows: 

It was noticed by him tliat a strain of tubercle bacilli which had been grown on 
glycerin agar and in glycerin V>eef broth for fourteen generations no longer destroyed 
guinea pigs as readily as it had previously done. In the case of the fourteenth gen- 
eration it required six months before the disease developed. He consequently inocu- 
lated a number of guinea pigs with the seventeenth, eighteenth, nineteenth, and 
twentieth generations of this germ. After some months the guinea pigs that had 
been inoculated with the attenuated germ remained quite well, and one which was 
chloroformed proved on examination to be free from disease. In order to test the 
immunity of these animals 4 guinea pigs w^hich had been inoculated with the attenu- 
ated germ and 4 check guinea pigs which had received no treatment were all inocu- 
lated with material obtained from a tubercular cow which had just been killed. 



56 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

After seven weeks the checks were all found dead from tuberculosis, while the treated 
animals all appeared perfectly well. One of these was then chloroformed and care- 
fully examined, but no trace of the disease could be detected. Even the local lesion 
that was produced where the material had been injected had entirely healed. He 
fed these attenuated bacilli to a calf and injected them intravenously into a cow with- 
out any disease being jiroduced. 

He concluded from these experiments that "our attenuated germ 
may pos.sibl}^ prove very valuable in checkino- or controllino- tubercu- 
losis in animals, especially cattle." 

The investigation of this attenuated tuberculosis bacillus was con- 
tinued by De Schweinitz and Schroeder/'' who in 1896 stated that their 
experiments showed conclusively that from an originally virulent 
germ they had succeeded in ol)taining an attenuated germ which even 
in large doses was apparently harniless to guinea pigs, rabbits, cattle, 
horses, and monkeys. They had inoculated cows and calves with this 
germ in doses var\'ing from 2 c. c. to 500 c. c. at a time without the 
production of tuberculosis. 

The history of one of the animals in the experiments of De Schwei- 

nitz and Schroeder*^ is very interesting, since it clearly indicates the 

possibilitj" of immunizing cattle against tuberculosis. 

A cow which had been previously tested with tuberculin received on July 26, 1894, 
an intravenous injection of 16 c. c. of an attenuated culture of the human tubercle bacil- 
lus. Tested November 19, no reaction to tul )erculin was noted. On November 2S, 6 c. c. 
of an attenuated culture was injected into the aV>dominal cavity. The injections were 
repeated at various times, the animal being kept in the experiment for t\vent3'-eight 
months and receiving altogether 20,870 c. e. of culture, of which as large an amount 
as 2,000 c. c. was given at one time. On February 22, 1898, this animal received an 
injection of virulent material taken from a cow affected with generalized tuberculosis. 
The injection was made into the thoracic cavity. The cow thus treated was killed 
September 20, 18i)8, and a careful autopsy, made by Doctor Schroeder, failed to dis- 
close the slightest evidence of tuberculosis. 

These experiments of De Schweinitz and Schroeder are in the nature 
of pioneer work for the immunization of cattle against tuberculosis. 
It is evident that they succeeded in obtaining attenuated tubercle 
bacilli which could Ije inoculated into guinea pigs and cattle without 
producing an}^ disease. It is also evident that they produced immunity 
in guinea pigs by inoculating them with this attenuated material, since 
four of these pigs resisted perfectly inoculation with virulent bovine 
bacilli which killed all the checks in seven weeks. And, finally, it 
seems evident that they produced immunity in a cow, since this animal 
was able to resist an intrathoracic injection of active bovine tubercu- 
losis virus; and not only did she show no symptoms of disease while 
living, but a careful post-mortem examination failed to reveal the 
slightest lesion of the disease at the point of inoculation or elsewhere. 
m'fady ban's experiments. 

McFadyean *** published some interesting experiments in 1901 which 

seemed to show that the animals used in his experiments had acquired 

a high degree of immunity. 

The first animal was a yearling heifer which received 9 doses of tuberculin of 
1 c. c. each, with intervals of three to eleven days. It was then given 8 doses of 
10 c. c. each, and following this 6 doses of 20 c. c. each. Thirteen days after the last 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 57 

dose of tuberculin was given this animal received an intravenous injection of 2 c. c. 
of a liquid very rich in tubercle bacilli, prepared by rubbing up some caseopurulent 
matter from the mesenteric gland of a horse with sterile water. On the same day 
(February 6, 1900) two other animals of about the same size and age were infected 
in the same way with a Mke quantity of the same material. These two animals, 
which may be regarded as checks, subsequently became ill, and when they were 
killed on the 10th of April their lungs were found to contain numerous tubercles, 
while the broncliial and mediastinal hnnphatic glands were greatly enlarged and 
caseating. The first animal mentioned had reacted to the first, second, fourth, and 
sixth doses of tuberculin, and then failed to respond even to the large doses until 
after it received the infecting material, when it responded twice to doses of 1 c. c. 
Later it was treated with tuberculin in doses varying from 5 c. c. to 20 c. c. without 
any important rise of temperature occurring. 

On May 22, 1900, this animal was killed, and a most searching post-mortem exami- 
nation revealed no lesion anywhere except in one mesenteric gland, which contained 
a completely calcified tubercle about the size of a pea. The assumption was that 
this lesion had been in active condition when the auimal was first tested, and that it 
was accountal)le for the reactions then obtained. It would appear that tlie experi- 
menter was more or less justified in concluding that this animal had latterly a very 
high degree of immunity against tuberculosis. 

The scxiond animal was a heifer about Ij years old. This heifer was tested with 
tuberculin on October 9 and 12 and November 27, 1899, and January 8, 1900, 
reacting each time. .The dose of tuberculin was 1 c. c. on each occasion. On Jan- 
uary 11 the animal received by intravenous injection IJ c. c. of a liijuid rich in 
bovine tuljercle bacilli, and another heifer was inoculated in the same manner as a 
control animal. The control animal was killed on March 2, 1900, when it was very 
ill, and the post-mortem examination revealed a dense miliary tuberculosis of the 
lungs. The experimental heifer was treated with tuberculin as follows: January 15, 
17, 21, and 2-t, and ]\Iarch 8, 20 c. c; March 15, 10 c. c, and March 28, 20 _c. c, with- 
out any distinct reaction occurring. April 5, 1900, this animal was again inoculated 
intravenously with 2 c. c. of a liquid obtained by triturating a jiortion of the fresh 
lung of a rabbit, Avhich was dead as the result of inoculation with bovine tuber- 
culosis, with sterile water. This inoculation did not occasion any recognizable dis- 
turbance, but the heifer reacted when tested with an ordinary dose of tuberculin 
June 13, July 18, and October 16. The test was rei)eated November 20, with an 
indecisive rise of temperature. November 28 a third intravenous injection of tubercle 
bacilli was made. The dose was 2 c. c. of a liquid obtained by triturating the tuber- 
cular material from the spleen of a horse with sterile water. The animal was tested 
with tuberculin December 19 and January 22 following, and reacted each time. 
January oO, 1901, the animal was inoculated for the fourth time intravenously with 
5 c. c. of a rich emulsion of tubercle bacilli from an artificial culture (origin not 
given). On the day following the injection the temperature had risen to 104.2° F. 
and remained at about that point until February 4. Tested May 15, it did not 
respond. May 18, a fifth intravenous inoculation with tubercle bacilli was made. 
The dose was 5 c. c. of a rich emulsion of artificial culture (origin not given). The 
same day the heifer's temperature rose to 105.6° F., but it gradually fell and was 
normal May 21. On June 18, 1901, the animal did not respond to an ordinary dose 
of tuberculin. At the time of reporting, the animal appeai'ed to be in perfect health 
and its general condition was good. 

The third animal was a heifer about a year old at the time the experiment began. 
It was tested with tu])erculin May 5, 1899, without reacting, and was in(jculated 
intravenously May 10 with 2.3 c. c. of an emulsion made from the tuberculous liver 
of .a pheasant which had contracted the disease naturally. Between May 11 and 
October 26 the animal was tested with tutjerculin nineteen times, reacting to the 
third, fourth, fifth, sixth, seventh, and eighth tests. November 11 the animal was 
inoculated intravenously with 2j c. c. of liquid containing tubercle bacilli fi'om the 
liver of a rabbit which had died after being inoculated with tubercular material from 
a horse. Between November 21 and January 8 she was tested five times with tuber- 
culin without reacting. On January 11, 1900, the animal received the thii'd intra- 
venous inoculation with tubercle bacilli, the dose being IJ c. c. of liquid containing 
bovine bacilli. As in the previous cases, the injection caused no obvious disturbance 
of the health, .^pril 5 a fourth intravenous injection was given, the_ material being 
a suspension of bovine bacilli and the dose 3 c. c. No symptoms of illness followed 
the operation, but the animal reacted to some of the subsequent tests with tuberculin. 
On November 28, 1900, the heifer was inoculated intravenously for the fifth time, 
receiving 2 c. c. of liquid containing bacilli from the spleen of a horse. In the tests 
following this inoculation no rise of temperature occurred. January 30,^ 1901, it was 
inoculated intravenously, this time with 5 c. c. of emulsion from an artificial culture. 



58 TUBEECULOSIS OF THE FOOD-PRODUCING ANIMALS. 

Oil March 23, 1901 , the heifer was inoculated intravenously with 15 c. c. and on May 18 
with 5 c. c. of an emult^ion of a culture of tuljercle bacilli. At the time of reporting, 
the general condition of the animal was fair and it appeared to be in good health. 

The fourth animal was a Shorthorn cow about 4 years old. It was tested with 
tuberculin and failed to react. September 29, 1898, it was inoculated intravenously 
with -t c. c. of a suspension of tubercle bacilli from the liver of a fowl. Following 
this inoculation the cow reacted to the tuberculin test. She was afterwards reinocu- 
lated intravenously with tubercle bacilli as follows: November 11, 1899, 4 c. c. of 
liquid containing tubercle bacilli from a horse; April 5, 1900, 3 c. c. of a suspension 
of bovine bacilli; March 23, 1901, 15 c. c, and May 18, 1901, 5 c. c. of an emulsion of 
a culture of tubercle Ijacilli. At the time of reporting, this animal was very fat, 
appeared to be in perfect health, and did not react to tuberculin. 

The report which has just been summarized carries the experiment 
up to about July 1, 1901. At that time the condition of the three 
animals remaining- alive was such as to lead to the conclusion that they 
had entirel}' resisted the inoculations with virulent tubercle bacilli and 
that they were consequently immune to the disease. The danger of 
reaching- an}^ conclusion in such cases in the absence of a post-mortem 
examination is strikingly illustrated by the subsequent history of these 
animals, for, although two of them appeared to be in ""perfect health " 
and the third in "good health," all three of them died of tuberculosis 
within eight months from the time the report was made. Notwith- 
standing this unfavorable termination of the experiment, its history 
is instructive in many respects, and particularly in showing the diffi- 
culty of innnunizing animals against tuberculosis. It is one of the 
failures which should be considered not less than the successes. 

The first of these animals was given a sixth inoculation July 31. The material 
employed was an artificial culture of tubercle bacilli rubbed up with sterile water so 
as to forn^ a turl)id li(juid. It was given a seventh inoculation October 24 of 10 c. c. 
of a licjuid rich in tuV)ercle bacilli made with the surface growth of a culture. 
December 16 the animal as usual ajipeared to be quite well, but in the early morn- 
ing of the 17th it was found down in its loose box and it died almost immediately. 
The post-mortem examination showed widely distributed lesions affecting the lungs, 
I^leura, kidneys, omentum, pia mater, and numerous glands. 

The second animal received a ninth inoculation July 21, 1901, of 5 c. c. of a rich 
emulsion of tul)ercle bacilli from an artificial culture. A tenth inoculation was made 
October 5 of the surface growth of a culture rubbed up with sterile water, the quan- 
tity injected being 10 c. e. October 24 it was inoculated intravenously for the 
eleventh time, the dose being 10 c. c. of emulsion of tubercle bacilli from an artificial 
culture. This animal died suddenly and quite unexpectedly December 23, 1901. 
Post-mortem examination showed tubercles in the lungs, bronchial and mediastinal 
glands, kidneys, and pia mater. 

The third animal received its sixth inoculation July 31 of 5 c. c. of the liquid used 
on that date for the preceding two cases, and the seventh inoculation October 5, 
which was also the same as was given to the other animals. An eighth inoculation 
was given January 22, 1902, of 4 c. c. of a liquid made by rubbing up a quantity of 
caseous material from the spleen of a horse with sterile water. On the morning 
of February 10 it was found that the cow was unable to rise, and the following morn- 
ing, as death appeared to be imminent, she was destroyed by chloroform. The post- 
mortem examination showed tul)ercu]osis of the kidneys, bronchial and mediastinal 
glands, lungs, pleura, tongue, and medulla oblongata.** 

WORK OF PEAliSON AND GILLILAND. 

Important experiments were published by Pearson and Gilliland ''" 
in 1902. One of these experiments was conducted to determine the 
immunizing (^.li'ect upon cattle of Koch's original tuberculin. 



MATEEIAli FACTS COT^CERNING TUBERCULOSIS. 59 

In this experiment 4 cows were nsed. Two of these cows were given daily injec- 
tions of 5 c. c. of concentrated tuberculin for ten days from August 24 to September 
2, 1901. All of the 4 cows were fed daily 100 grams of hacked tuberculous lung 
tissue from a cow for ten days from September 10 to September 19. The 2 cows that 
had received the preliminary treatment with tul)erculin were each given 15 c. c. of 
concentrated tuberculin while they were being fed upon the tuberculous material. 

One of the cows that had been treated with tuberculin and one of those that had 
not been so treated were killed November 2.5, 1901. The cow that had been treated 
with tuberculin showed lesions of tuberculosis in the postpharyngeal and mesenteric 
lymphatic glands. The control cow had lesions in the right lung and in the post- 
pharyngeal, intermaxillary, bronchial, mediastinal, and mesenteric lymphatic glands. 
The lesions in this control cow were more widely distributed and more advanced than 
in the cow that had received large quantities of tuberculin. 

The remaining 2 cows of the experiment were killed December 16, 1901. In the 
first of these cows which had received the injections of tuberculin no lesions of tuber- 
culosis were found excepting in the mesenteric lymphatic glands. A few of these 
glands of l)oth the small and large intestine showed small areas of caseation. The 
second, or control, cow showed lesions of tuberculosis in both lungs, in the bronchial, 
mediastinal, and postpharyngeal lymphatic glands, and in the l}inphatic glands of 
the mesentery, the last-mentioned glands being more extensively involved than were 
those in the cow which had received the treatment with tuberculin. 

The conclusion from this exj^eriment was that the administration of the tuberculin 
had had some effect in increasing the resistance of these 2 cows to infection from 
feeding tulterculous material. 

The next series of experiments reported was made to throw some light upon the 
question as to the quantity of culture of tubercle baidlli derived from human sputum 
which might be administered and the effect of repeated inoculations made in four 
different ways, it having been already determined that such cultures were usually 
comparatively nonvirulent for cattle. In these experiments there was used a stand- 
ard suspension of tubercle bacilli in water, made in such proportions as to give an 
opacity ecpial to that of a 24- hour culture of typhoid bacilli in bouillon, and 1 c. c. of 
such a culture was estimated to contain the equivalent of 0.0013 gram of tubercle 
bacilli dried ten days in a desiccating chamber over calcium chloride. 

The first animal treated was a Jersey heifer, shown by the tuberculin test to be free 
from tuberculosis. The inoculations of this animal were as follows: 

September 29, 1900, 4 c. c. intraperitoneally; March 15, 1901, 1.3.5 c. c. intrave- 
nously; June 1, 1901, 10 c. c. intravenously; August 23, 1901, 20 c. c. (5 c. c. beneath 
the skin, 5 c. c. into the ])eritoneal cavity, 5 c. c. into the jugular vein, and 5 c. c. into 
the lung) . These injections were repeated with intervals of seven to ten days until 
January 29, 1902, the dose being increased 10 c. c. with each successive inoculation, 
so that at the last, the eighteenth, the total quantity given was 160 c. c. 

The total quantity of standard suspension of human tubercle bacilli administered 
to tins heifer was 1,797 c. c. There was a rise of temperature of from 2° to 4° follow- 
ing each inoculation after the first one. The first inoculation caused no tempera- 
ture reaction. The animal was in strong, thrifty condition at the completion of the 
series of inoculations, and continued to improve until it was killed, August 14, 1902. 
It was found free from tuberculosis. 

The second animal treated was a grade Shorthorn bull, which did not react to 
tuberculin. This animal was inoculated as follows: 

November 19, 1900, 16 c. c. intraperitoneally; March 17, 1901, 13.5 c. c. intra- 
venously. Subsequent inot-ulations were the same as with the preceding animal, 18 
being given between August 23, 1901, and January 10, 1902, the total amount being 
1,710 c. c. 

This animal reacted very much as the heifer, although somewhat more slowly. 
He remained in good condition and apparent good healtli. On January IS, 1902, 
this bull was inoculated intraperitoneally with lO c. c. of a standard suspension of 
bovine tubercle bacilli. This culture had been tested and found to be fatal for cat- 
tle in doses of 5 c. c. intravenously or intraperitoneally within three to eight weeks. 
The bull remained in good condition until killed for examination August 13, 1902. 
The lungs were found to contain a few nodules about one-half inch in diameter, 
surrounded by thick walls and containing caseous pus in which were many tubercle 
bacilli. These nodules did not seem to be progressive, and appeared to be abscesses 
indicating the sites of previous inoculations. The lymphatic glands about the 
rectum were enlarged and caseous. The pleura and peritoneum were covered with 
a layer of partly organized fibrin. 

It was thought that the results of the experiments with these two animals showed 
that the sputum tubercle bacilli, even in the very large quantities in which they 
were employed, were incapable of causing general tubercular infection, and that the 



60 TUy^EROULOSIS OB^ THE FOOD-PRODUCING ANIMALS. 

experiment witli the latter (the bull) indicated that by treatment with such mate- 
rial the resistance to virulent bovine bacilli may be increased. 

A further experiment, to test the immunizing value of repeated intravenous inocu- 
lations of sputum cultures of tuljercle bacilli not virulent for cattle, was inaugurated 
in March, 1902. Four young cattle were used in this experiment, which were 
divided into two groups as nearly equal as possible in respect to age, size, and gen- 
eral condition. The animals of one group were inoculated intravenously seven times 
between March 24 and June 2 with gradually increasing quantities of from 10 c. c. 
to 25 c. c. of standard suspension of tubercle bacilli. In all 125 c. c. were adminis- 
tered, rejiresenting about 0.16 gram of tuliercle bacilli. 

Each of the four animals — the two that had been vaccinated and the two kept as 
controls — was inoculated July 29 l)y injecting into the trachea 10 c. c. of a standard 
suspen.^ion of bovine tubercle bacilli known to be virulent for cattle. 

One of the vaccinated cattle was killed October 4 and a searching post-mortem 
examination revealed all of the organs to be free from all evidence of tubercular 
disease. 

A control animal killed October 8 showed the following lesions: Beneath the skin 
at the point of inoculation there was a globular abscess three-quarters of an inch 
in diameter, containing cheesy pus. The lungs were studded upon.the surface and 
upon cross section with grayish tubercles one-fourth to one-half inch in diameter, 
the centers of which were caseous. The apex of the right lung contained a caseous 
area 2 inches in diameter. The postjtharyngeal, l^ronchial, and mediastinal lym- 
phatic glands were enlarged and contained cheesy areas. 

Tlie second vaccinated animal was killed October 16, and all of the organs of the 
body were found free from disease with the exce]ition of two globular swellings one- 
fourth to three-tifths of an inch in diameter, respectively, at the point of inoculation. 
One of these was made up of fibrous tissue and the other contained a focus of caseous 
material surrounded by thick, fil)rous walls. 

The second control (unvaccinated) heifer was killed October 16, and presented 
the following lesions: Beneath the skin at the point of inoculation was an abscess 2 
inches in diameter that contained cheesy pus. All of the inferior cervical and supra- 
sternal lymjih glands, as well as the postpharyngeal, mediastinal, bronchial, and many 
rif the mesenteric lymphatic glands were greatly enlarged and contained much case- 
ous material. The mucous membrane of the trachea was, on its ventral half, thickly 
studded with olilong, red, and evidently young and progressive tubercular growths. 
The lungs contained many tubercles evenly distributed throughout their tissue and 
averaging 4 to 5 inches apart, the smaller of which were gray, Avhile the larger had 
yellow, cheesy centers. 

VON behring's investigations. 

A long series of investigations relative to the production of imniu- 
nit}" in cattle has l)een made by Von Behring,"^ whose first paper on 
the sui)iect was published in December, 1901. His method has been 
modified from time to time, but he has no doubt succeeded in produc- 
ing a high degree of inmiunity in some of his experimental animals. 
His work has been of much value in showing the effect of diti:erent 
doses of human tul)ercle bacilli when inoculated upon cattle, as well 
as in directing jittention to immunization as a practical means of com- 
bating tuberculosis in cattle. As the result of experiments with 
several hundred young cattle, he states that one of his weaker cultures 
in doses of one-tenth of a milligram injected intravenousl}^ does not 
produce the slightest eflect upon the animal either as to its appearance 
or temperature. Infection with 1 milligram of this culture causes a 
slight rise of temperature, not exceeding 1^ C, which as a rule is fol- 
lowed ))y a return to the normal temperature after two or three days. 
Doses of 1 centigram and larger amounts cause very threatening 
symptoms, ))ut with the largest doses used the disease developed was 
not so great but that the animals made a complete recov. ry. The 



MATEKIAL FACTS OONCERNHSTG TUBERCULOSIS. 61 

post-mortem examination of an animal which had received an intra- 
venous injection of 2 centio-rams of this culture showed that no point^^ 
of disease remained in the body. 

The method first recommended for protectin^^ animals in practical 
operations was to take cattle from 5 to 7 months of ag-e that did not 
react to the tuberculin test and to give by intravenous injection, as the 
first dose, i milligram of a serum culture 4 to weeks old. Four 
weeks later the animal was given in like manner a dose of 25 milli- 
grams of the same culture. In his later papers Von Behring recom- 
mends the use of this same culture after it has been dric^d in a vacuum 
at a low temperature. In order to immunize cattle this is suspended 
in 1 per cent salt solution and given by intravenous injection. The 
first dose is 4 milligrams, and the second dose, which is to be given at 
the earliest twelve weeks after the first dose, is 2 centigrams. 

The inoculation material, or ''vaccine,''' is furnished in the dry 
powdered form, and is supposed to remain active for at least four 
weeks. The powder is of course made up of an enormous ruimber of 
human tubercle bacilli, which are so minute and light that they are liable 
to be taken up by slight currents of air, and unless suitable precautions 
are taken they ma\' be breathed by the persons present at the time they 
are examined or when they are being prepared for use in immunizing 
cai^tle. This form of vaccine is therefore considered objectionable and 
unsafe b}" some authorities, and the preference is given to immunizing 
material which is prepared in the laboratory in liquid form. 

The cattle immunized by the Yon Behring method appear to acquire 
a considei'able degree of imnmnity, but some of them certainl}^ have 
not had sufficient to enable them to resist fatal doses of the bovine 
tubercle bacillus. It is believed by Von Behring that immunization 
b}^ this method will protect cattle against natural infection when they 
are exposed in stables to diseased cattle; but, unfortunatel}", some of 
the cattle reported upon as tested were not immunized b}^ the latest 
process which he recommends, and consequently do not furnish an 
indication as to its value. Further experiments will be required to 
establish the efficacy of Von Behring's method, and particularly to 
determine the length of time that the dried tubercle bacilli will retain 
their activity under the different conditions to which the}^ are likely to 
be exposed. 

To protect the operator from the danger of manipulating bacilli used 
for the preparation of the vaccinal emulsion, and to render this as 
homogeneous as possible, Vallee and Panisset '^" reconnnend th(> follow- 
ing plan of procedure: 

Grind the dried bacilli with 2 or 3 drops of glycerin in a short-necked Wurtz 
matrass, using glass balls, then emulsionize progressively in the desired quantity (2 c. c. 
for 4 milligrams of bacilli) of physiological serum having 8 per 1,000 of chloride of 
sodium to which is adde<l li grams per 1,000 of carbonate of sodimn. The addition 
of this salt favors the homogeneousness of the emulsion and has no injurious effect 
upon the animals or upon the vaccine. 



62 TTTBEEOULOSIS OF THE FOOD-PRODUCING ANIMALS. 

In November, 1902, Doctor Von Behring' sent 2 bovine animals pro- 
tected by his method from Marburg- to the university at Leipzig- for 
the purpose of being tested as to their degree of resistance ag-ainst 
artificial infection with l)Ovine tuberculous material. The tests were 
carried on during the autumn of 1904. 

No. 1 had received intravenous injections of bovine tubercle bacilli, the activity of 
which had been diminished by treatment with trichloride of iodine, followed by 
intravenous injections of bovine tubercle bacilli dried in vacuo, and an injection into 
the anterior chamber of the eye of virulent human tubercle bacilli. The eye became 
tul)ercalous and was removed by operation. Finally the animal was subjected to a 
series of six injections with increasing quantities of fresh human tubercle bacilli. 

No. 2 had previously Ijeen injected with dead human tubercle bacilli cultivated in 
the rat and with fresh human tubercle bacilli. Following this it had received an 
intravenous injection of fresh bovine tubercle bacilli, ami finally it had been twice 
inoculated intravenously with avian tubercle bacilli dried in vacuo. 

Both animals were gradually infected, subcutaneously and intravenously, with 
bovine tubercle material, 6 other tubercle-free young cattle being employed as con- 
trols. Two other young cattle were utilized for the purpose of controlling the method 
of feeding and the general hygienic conditions. 

The general conclusion arrived at was that the animals treated by the Marburg 
method showed a greater degree of resistance against artificial, subcutaneous, and 
intravenous infection with bovine tubercle virus than those not treated. The grounds 
for this conclusion were: 

1. The absence of any local change at the point of inoculation when infected with 
slightly virulent material, which in control No. 6 jiroduced tuberculous infiltration 
at the jioint of inoculation and tuberculous enlargement and caseation of the neigh- 
boring lympli glands. 

2. The very trifling changes at the point of inoculation and the absence of any 
tuberculous change whatever in the local lymph glands in No. 1 when subcutane- 
ously inoculated with very virulent material, which caused in control No. 13 exton- 
sive infiltration and ulceration at the point of inoculation, extensive swelling and 
caseation of the neighboring lymph glands, and embolic tuberculosis of the lungs, 
liver, and spleen. 

3. The absence of any kind of tuberculous change in neighboring lymph glands 
even in cases where subcutaneous injection of very virulent material led to the 
formation of a caseous tuberculous abscess at the point of inoculation and isolated 
embolic tubercles in the kidneys (No. 2). 

In control No. l-l the subcutaneous injection of similar material produced exten- 
sive tuberculous infiltration at the point of inoculation, extensive tuberculous swel- 
ling and caseation of neighboring lymph glands, and embolic tuberculosis of the 
lungs and spleen. 

4. When virulent tubercle bacilli were injected into the veins the increased resist- 
ance was principally shown by the trifling degree of general disturbance produced 
and by the speedy and substantial improvement in the condition of the protected 
animal, which coii tinned to live for five months and three weeks longer. Tlie animal 
was eventually slaughtered on account of acute brain disease, probably of tubercu- 
lous origin. Controls Nos. 21 and 22, injected with a similar amount of virulent 
material, died in twenty-eight and thirty-eight days, respectively. 

TIk; ])rotected animals were by no means absolutely proof against the disease. 
When the (juantity administered was sufficient both animals suffered from tuberculous 
infection. 

Thetul)erculin test is unreliaV)le in cattle previously treated with attenuated bovine 
or hmnan tubercle bacilli unless a long period (not less than six months) has 
elapsed since the last infectious material was injected. The pi'otected animals did 
not react to tuberculin even when they were suffering from tuberculous changes both 
at the jwint of inoculation and in their internal organs. As neither of the protected 
animals was immunized by the double inoculation method with weakened human 
tubercle bacilli according to Von Behring's present method, the foregoing conclusions 
must not be apj^lied to this method. 

E))er" considers the results so far obtained from this and other 
experiments as very encouraging. 



MATEKIAL FACTS CONCERNING TUBERCULOSIS. 63 

EXPERIMENTS BY HUTTRA. 

Some important experiments were made by Hutyra,'^* under com- 
mission of the Hungarian department of agriculture, in order to 
determine to what extent vaccination according to Von Beh ring's 
niethod increases the immunity of cattle against artiticial infection 
with virulent bovine tubercle bacilli. 

Two calves 9 months old were treated witli Von Behring's vaccine. The first dose 
was 0.004 gram, and forty days later a second dose of 0.01 gram was administered. 
Two months after the second vaccination both of these animals, together with 2 
control animals of the same breed, received an intraA'enous inoculation of O.Oj gram 
of virulent l)Ovine bacilli. Two weeks after this infection the control animals were 
very sick, and one was killed at the end of fdur weeks and the other at the end of 
six weeks from the inoculation, both being in a dying condition. The examination 
showed with both animals an extensive miliary tuberculosis of the lungs and jiectoral 
lymph glands. The vaccinated animals quickly recovered from the reaction follow- 
ing the infection, but had some fever afterwards, though their weight increased and 
they presented no other 8ymi)toms of disease. They were killed two and one-half 
months after infection, and examination showed in both cases slight tuberculosis in 
isolated parts of the lungs and in the pectoral lymphatic glands. 

An animal of the same breed and age as tiiose in the experiment just reported was 
likewise twice vaccinated. Two months after the second vaccination this animal 
and a control animal were given a subcutaneous injection of 0.02 gram of a culture 
of virulent bovine bacilli. The effect with the two animals was much the same, only 
there developed at the point of inoculation in the control animal a much larger 
swelling than with the vaccinated animal. The animals Avere killed two and one- 
half months later, and there was found in the vaccinated animal onl}' a caseous spot 
the size of a bean at the jioint of inoculation, with enlargement of the corresponding 
prescapular lymph glands, while with the control animal there was not only an 
extensive lesion at the point of inoculation, but there were tubercles in the lungs, 
spleen, and kidneys, and the beginning of jiearl disease on the pleura. 

In another experiment 4 young cattle from 9 to 12 months old were twice vaccin- 
ated with Von Behring's material with an interval of forty days. After two months 
had elapsed these animals with two controls were fed with cultures of virulent bovine 
bacilli, which had no apparent effect upon their health. Five months after the second 
vaccination, and two months after the animals were fed with bovine culture, all 6 
calves were given an intravenous injection of 0.025 gram of a culture of bovine bacilli. 
All of these animals gave a strong temi>eratnre reaction. While, however, with 2 of 
the inoculated calves the al)normal sym})toms soon disappeared, with a third the 
fever continued and there was little gain in weight, and with a fourth the result was 
so serious that it was necessary to kill the animal five weeks later, it being then very 
sick, and the post-mortem examination showed extensive tuberculosis of the lungs and 
lymph glands. Both control animals became very sick after the infection, and on 
post-mortem examination were found to have extensive tuberculosis of the lungs and 
lymph glands, and one of them had Ijesides tubercles and tu))ercular ulcers of the 
intestinal mucous membrane. The r> vaccinated animals which remained living were 
killed three months after the intravenous infection and showed moderate tubercular 
lesions in the lymjih glands of different ])arts of the body. With one there was a 
focus of catarrhal i)neumonia in the lungs and with another there were soft growths 
up to the size of a bean upon the pleural and peritoneal surfaces of the diaphragm. 
Decided lesions from alimentary infection were only present in one case and with 
this the infection had occurred through the mucous membrane of the throat. 

A final experiment was made with different stocks of tubercle bacilli; one of these 
was from a monkey and two from human sources. The cultures of the three stocks 
presented the peculiarities of human tubercle l)acilli. For vaccination, cultures 4 
weeks old which had lieen grown on glycerin potato were used without being dried, 
each animal receiving the first time 0.005 gram and five and a half weeks later 0.025 
gram injected into the jugular vein. The animals were 'Sh to 9 months old. There 
was no increase of temperature following the first injection, but after the second 
injection 2 animals had a fever lasting two days. Seven weeks after the second 
vaccination all 3 animals, with a control, received 0.02 gram of a glycerin-potato 
culture of virulent bovine bacilli by injection into the jugular vein. The vaccinated 
cattle had, as a result of this inoculation, a marked increase in temperature, which 
subsided and left the animals in a normal condition.' Three months after the inocu- 
lation with bovine bacilli the 3 animals were killed, and showed on examination 



64 TUBERCULOSIS OF THE FOOD-PEODUCING ANIMALS. 

insignificant tuberculous lesions in the internal organs. In one case the lungs were 
entirely healthy and only a fresh connective tissue growth on the costal pleura led 
to the suspicion that it was caused by the inoculation. In a second case the peri- 
l>ronchial lynii)h glands alone contained very small calcified tubercles. In this 
experiment the tubercle bacilh from the monkey and from the two human sources 
produced even more favoraljle results than were obtained in the first experiment 
with Von Behring's oi'iginal vaccine. 

A jjeculiar behavior toward tuberculin was observed with these cattle which had 
been twice vaccinated and afterwards infected with virulent bovine bacilli. Of 6 
cases which were tested with tuberculin two and one-half months after the virulent 
infection, 5 cattle did not react at all, and with 1 only was there a rise of temperature 
from 39° to 40.8° C. Tubercular lesions were found in 5 of these animals at the 
post-mortem examination. This striking insensibility of the first 5 cattle to tuber- 
culin recalls tlie similar behavior of cattle which as a result of natural infection are 
already very sick, as well as of those which had a short time ])reviously received a 
larger dose of tuberculin, in which cases it often happens that no reaction occurs. 
It appears, therefore, that as a consequence of a heavy infection or a saturation of 
the organism with the toxic i)roducts of the tuberculosis bacilli the sensibility toward 
tuberculin, or at least toward small doses of tuberculin, becomes for a certain time 
lessened. 

Hutyra"'^ stated in his report to tlie International Veterinary Con- 
gress at Budapest in 1905 that his conchisions in regard to the immu- 
nization of bovine animals against tuberculosis were at follows: 

An intravenous injection, once repeated, of human tubercular bacilli, after Von 
Behring's method or some similar one, increases to a very considerable extent the 
power of resistance in cattle to artificial pearl-disease infection. 

The process is innocuous to sound cattle, and presents no difficulties in its carrying 
into practice. 

The question whether, and if so, how far, the immunity produced in this way 
extends to natural infection, finds no solution in the results of past exjterience; to 
solve this problem accurate observations of inoculated animals, continued for years, 
will still be nec(>ssary. 

A similar inoculative protection against artificial infection is apparently afforded 
by a single subcutaneous injection with cultures of human tubercular bacilli. 

thomassen's experiments. 
Experiments made by Thomassen''^ in 1902 indicate that consider- 
able immunity may l)e produced b}^ inoculating cattle with human 
bacilli. 

A young bull received l)y intravenous injection January 9, 1902, 30 milligrams of 
human bacilli which had been cultivated on potato since July, 1900. The bacilli 
were given fresh. If 'dried they would have been reduced to about 6 or 7 milli- 
grams, and besides, desiccation reduces the virulence of tubercle bacilli. Until 
January 22 the animal presented no symptoms, but on that date the temperature 
commenced to rise, and on the 23d reached 40.9° C. The temperature continued to 
fluctuate between 40° and 41° C. until the first days of February. The animal con- 
tinued to drink milk but did not gain in weight and its appearance was not satisfac- 
tory. From the 7th of February the temperature became normal, and toward the 
beginning of March the calf gained in weight and appeared to be in perfectly normal 
condition. April 29 tiie animal "was tested with tuberculin but did not react. The 
immunity was tested by intravenous injection June 12 of 40 milligrams of culture of 
bovine bacilli. The day of the injection a marked rise of temi)erature was noticed, 
which persisted for five days, but the api)etite remained normal, the respiration did 
not increase in frecjuency, and there was no cough. The animal reacted when tested 
with tu))erculin August 17, and was killed for examination September 25. The 
autopsy revealed about ten tubercles in each lung, some of which were as large as a 
pea, but the majority were the size of a millet seed. Guinea pigs inoculated from 
these tubercles died of generalized tuberculosis. A single bronchial gland contained 
some tubercles, but guinea pigs inoculated from this gland did not contract the dis- 
ease. The clinical symptoms would indicate that the few lesions observed exclu- 
sively in the lungs, and that might be considered as in process of healing, had been 
produced by the infection with the human bacilli; but the tuberculin test, on the 
contrary, would lead to the conclusion tliat the slight infection which was found 
dated from the injection of the bovine bacilli. Even if the latter supposition were 



MATEEIAL FACTS CONCERNING TUBERCULOSIS. 65 

correct, the animal appeared to possess a degree of immunity which is seldom seen 
in animals which have not been immunized. 

As a control animal to determine the virulence of the bovine bacilli, calf No. 2 
was used. This animal was given 30 milligrams of the fresh culture by intravenous 
injection on June 28. This inoculation caused at first but a slight increase in tem- 
perature, which increased July 9 to 41° C. and remained above that point for about 
a week. The animal remained constantly in a recumbent jjosition and died July 17. 
On examination the lungs were found studded with recent miliary tubercles. 

Calf No. 3 received March 4, 1902, by intravenous injection, 25 milligrams of human 
tubercle bacilli, which had been passed once through a guinea pig and cultivated for 
three months on potato. The only symj^tom caused by this inoculation was a slight 
rise in temperature. Without testing with tuberculin, this calf was infected June 11 
with 40 milligrams of fresh bovine bacilli, such as were used in the inoculation of 
No. 2. The animal neither coughed nor lost appetite and its condition remained 
good. It was tested August 17 and reacted, and was again tested with a like result 
October 16. It-received a third infection November 3 by intravenous injection of 45 
milligrams of bovine bacilli, which produced no symptom other than a slight rise of 
temperature lasting about a week. This calf was killed December 18, and the exami- 
nation revealed a considerable number of tubercles in the posterior jiart of the two 
lungs. These tubercles were all calcified to such a degree that it was impossible to 
make a section of them with a bistoury. After crushing and examining these tuber- 
cles no bacilli could be discovered. Three tubercles were found in a bron(^hial gland 
which were less advanced in retrogression, but it was not yet determined whether 
they contained tubercle bacilli. 

Calf No. 4 was inoculated February 6, 1902, in the anterior chamber of the eye with 
a few drops of an emulsion of human bacilli. From February 15 to March 7 there 
was an increase of temperature varying from 0.5° to 1.7° C. Tested with tuberculin 
April 29 and August 17, it reacted on both occasions. September 3 this calf was 
given by intravenous injection 30 milligrams of a culture of bovine bacilli. During 
the twenty-four hours following this injection the temjierature rose to 40.2° C, but 
no other symptom was noticed for several days. Beginning with September 12, the 
animal coughed and had frequent respiration, but these symptoms disappeared after 
a few days. October 11 it was tested with tuberculin and reacted. This calf was 
killed October 24, and the most careful examination did not reveal the least lesion 
in either the abdominal or thoracic organs. Two guinea pigs were inoculated with an 
emulsion made from a suspicious gland, but no effect was produced. The posterior 
chamber of the eye contained a caseous mass in which were some calcified jjoints, 
and in this tubercular material the bacilli could still be found. A retropharyngeal 
gland was also affected. 

Calf No. 5, 12 days old, was given 8 milligrams of a fresh culture of bovine bacilli 
September 8. During the first week the temperature rose a little above the normal, 
but it was only from the fifteenth day that there was a considerable rise. The tem- 
perature became normal October 30, but during this month there had been little or no 
gain in weight. November 3 it received an fntravenous injection of 30 milligrams of 
the same culture, which immediately caused a marked rise in temperature. It 
coughed, drank only half of its milk, and had rapid respiration. From the eighth day 
after the inoculation its general condition considerably improved, and by the eleventh 
day it was very nearly in the condition in which it was before the second infection. 
Desiring to learn the character of the lesions proauced by the injection of the 8 mil- 
ligrams of bovine culture the investigator killed the animal on November 12, and 
the examination showed a number of miliary tubercles in the lungs containing bacilli 
capable of infecting guinea pigs. The bronchial glands Avere also affected. 

From these experiments it was concluded that bovine animals bear very well a 
dose of 30 milligrams of a culture of human bacilli injected directly into the veins. 
Also that a first infection does not cause a rise of temperature until ten or fifteen 
days after the inoculation, while with the second or third infection with bacilli the 
increase of temperature appears within twenty-four hours. 

After experimenting with different inetliods of immunization for 

more than three years, Thomassen " reaches the following- conclusions: 

1. It is now established that it is possible to obtain a certain degree of active 
immunity in regard to tuberculosis. 

2. The immunization of young cattle is a powerful addition to the means of hasten- 
ing the extinction of tuberculosis. 

3. It should be undertaken, after testing with tuberculin, as early as possible — i. e., 
at the age of 6 weeks, when the animal has not yet been exposed to the danger of 
contamination. 

1881— No. 38—06 5 



66 TUBERCULOSIS OF THE FOOD-PRODUCHSTG ANIMALS. 

. 4. The use for this purpose of human baeilH, of a low degree of virulence, and in a 
fresh condition, is preferable to that of other vaccines which are mentioned. 

5. For the first injection 1 milligram of Ijacilli is used, which may be preceded by 
a few injections of bovine tuberculin (this is highly recommended, i)articularly for 
animals only a few weeks old). Tlie dose is increased each time, at a month's 
interval, to 10 and then to 20 milligrams. The intravenous injection of bacilli should 
never cause the formation of an abscess at the jjoint of injection. 

6. Care should especially be taken to crush perfectly the bacilli, so as to prevent 
pulmonary lesions of embolic origin. 

7. The application of the vaccination on a large scale will be attended, in jiractice, 
with difficulties; among others the danger resulting to man from the manipulation 
of virulent products. 

8. It is very important to determine accurately the duration of the immunity 
following the vaccination. 

9. It may be admitted that the animal will be better able to resist the influence of 
a natural infection than that of a large quantity of bovine bacilli of great virulence 
placed directly in the circulation. 

KLIMMER's INVESTIC4ATIONS. 

Very important experiments in immunization have recentl}^ been 
reported by Klinmier,^^ of Dresden. This investigator made a number 
of experiments with reference to the moditication of the virulence of 
the tubercle bacillus by passing- it through different cold-blooded 
animals. By long-continued experiments with carp it was observed 
that b}^ living in cold-blooded organisms the tubercle bacillus gradu- 
ally lost its virulence, and when guinea pigs were inoculated with it 
the period of incubation and the duration of the disease were increased. 
By the use of a species of salamander in such experiments the tubercle 
bacilhis finally lost entirel}^ its virulence for manmials. The culture 
of this fully acid-fast avirulent tubercle bacillus had the same appear- 
ance as that of the human tubercle bacillus. Rabbits and guinea pigs 
inoculated with large quantities of this bacillus remained in a health}^ 
condition. Even the intravenous injection of 1 centigram of the 
culture failed to produce any tubercular changes in the organs. 

After the harmlessness for mammals(5f the avirulenttubercle bacillus became known, 
experiments were made with it for the inununizatiuu of animals against tuberculosis. 
For this purpose ra))bits and cattle were used. The vaccinations were made partly 
by intravenous and partly by subcutaneous injection, and the testing of the immunity 
was conducted by natural as well as by artificial infection experiments. The raljbits 
immunized with the avirulent tubercle bacillus were in the first place tested by arti- 
ficial infection with a stock of human tubercle bacilli which was pathogenic for 
rabbits, and it was demonstrated in this way that these animals had acquired abso- 
lute immunity against human tubercle bacilli. Afterwards the inununized rabbits 
were tested by infection with a very virulent bovine bacuUus and proved to have 
acquired a very high or even absolute immunity against this active germ. 

Cattle were given intravenous injections of the avirulent tubercle bacillus without 
causing any injury to their health, and tolerably large quantities were injected sub- 
cutaneously without producing either local or general disturbance. The immuniza- 
tion was carried out with several animals by intravenous injection and with others 
by subcutaneous injection, and the inununized calves were afterwards tested paitly 
by natural and partly by artificial infection. These animals showed a complete 
resistance to natural infection up to the time of reporting, and during the period of 
a year which ha<l elapsed, although the animals were repeatedly tested with tuber- 
culin, none had reacted, while the control animals had shown 3.3 to 36 per cent of 
positive reactions. The experiments with artificial infection were not completed at 
the time of reporting. 

Klimmer also used for immunizing cattle an attenuated human bacillus, which 
w^as harm-less both for the persons using it and for the animals. It was obtained by 
making pure cultures directly from the original source and without jmssage through 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 67 

any animal. In order that the use of this material for vaccination might be harm- 
less for the veterinarian it was not furnished in the dry condition from which it is 
easily transformed into dust, thereby becoming dangerous, but was taken directly 
from the culture and made into a suspension in the laboratory where it was culti- 
vated, so that it could be used in practice for immunizing without further manipula- 
tion. This suspension of bacilli remains unchanged and retains its immunizing value 
for four weeks. In order to reduce to a minimum the danger of infection through 
accidents and awkwardness, the tubercle bacilli are artificially attenuated in their 
virulence by heating at 52° to 53° C. Such an attenuation of the vaccination mate- 
rial does not affect its immunizing value. 

The use of this suspension of attenuated tubercle bacilli by intravenous injection 
into cattle is harmless, and even subcutaneous injections produced no lot:al swellings 
with calves, whereas suspensions of the unattenuated bacilli caused swellings from 
the size of a nut to that of a goose egg, with the foruiation of abscesses. From the 
exi)erience so far obtained it appears that cattle may be immunized by subcutaneous 
injection of this attenuated vaccine material. This simplities the operation, as the 
intravenous injection requires more time and is more difficult. 

Klimmer is of the opinion that the tubercle bacilli used for this purpose should 
not have been cultivated too long on artificial media, and tliat they should have 
acquired as little as possible of the saprophytic habit of growth. 

Such vaccine material made in the Dresden Hygienic Institute has been practi- 
cally tested since 1903 on a royal estate near Dresden, where the avirulent bacillus 
has also been used. Over 80 per cent of the cows and over 40 per cent of the young 
cattle at this place reacted to tuberculin. The immunized calves were, therefore, 
exposed to a heavy infection, especially as they were stabled among the tuberculous 
animals. In the two years during which the investigations have been in progress it 
has been established that the immunization of calves with this vaccine is free from 
danger. No losses have occurred from vaccination. Of about 60 calves treated, 
some have been slaughtered and others have died from various causes, but in none 
of these could signs of tuberculosis be discovered. Neither have any of the immu- 
nized animals reacted to tuberculin. The immunized calves developed in a superior 
manner, proving that the immunization had no detrimental effect uj^on them. 

The immunized calves and the control calves, which have been standing mixed 
together almost since their birth, have been tested with tuberculin. Of the control 
calves, which of course were not immunized, 14 were tested at one time and 6 
reacted, and at another time 10 were tested and 3 reacted. Of the calves immu- 
nized with the Dresden vaccination material not a single one has reacted, neither 
when tested a month after innnunization nor when the test was made one and one- 
half years afterwards. 

WORK OF KOCH AND OTHERS. 

In a recent and very important paper Koch, Scliiitz, Neufeld, and 
Mieszner^" state that in their experimental investigations they grad- 
ually reached a simple and safe method by which animals could be 
given a high degree of immunit}^ by one or two injections of living 
cultures of tubercle bacilli. With cattle the}^ obtained a complete 
immunization with only two injections, using at first an attenuated 
culture of the bovine bacillus. Tlie following striking experiment 
illustrates this fact: 

Calf XIII, weight 345.4 pounds, received an intravenous injection of 1 centigram 
of an attenuated bovine culture on August 25, 1902. A second injection of a like 
amount of the same culture was adminisered in the same manner October 17, 1902. 
The degree of immunity which this calf had acquired by these treatments was tested 
by injecting intravenously 1 centigram of a virulent bovine culture December 24, 
1902, a control calf being inoculated at the same time and in the same manner with 
a like amount of the virulent culture. As a result of the inoculation with the viru- 
lent culture, the unprotected control calf died January 16, 1903, with miliary tuber- 
culosis of the lungs. The protected calf resisted the inoculation, and when killed, 
on August 11, 1903, was found healthy. 

A degree of immunity which is sufficient to protect completel}^ an 
animal from such a virulent bovine germ as was used to test this calf, 
and which may be conferred by two vaccinations, is worthy of very 



68 



TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 



serious attention. A table has therefore been prepared by condensing 
a more complete one given by the authors which presents the impor- 
tant facts relative to a series of experiments since made by them. 

All of the calves used in these experiments were first tested with tuberculin and 
none were taken which showed a rise of temperature of more than 0.5° C. The 
second vaccination generally was made after the calves had fully recovered from the 
effects of the first, which required from four to six weeks. After the first vaccina- 
tion there was an increase of temperature to 40—41° C, which continued for several 
days, and following this a high normal temperature was observed for about two 
weeks, during which time there was either a marked gain or loss in weight. After 
this the temjaerature subsided and the animals recovered so completely that the 
second vaccination was made without hesitation. The second vaccination was fol- 
lowed by an immediate rise in temperature, which lasted only a few days and did 
not disturb the general condition of the animals. 

In order to test the imnmnity the calves were inoculated intravenously with 2 cen- 
tigrams of virulent bovine culture, which was so active that one-fortieth of this dose 
was sufficient to produce a fatal case of acute miliary tuberculosis in a calf within 
twenty to thirty days. This test is referred to in the table as the control injection. 

The table follows: 

Principal facts relative to recent immunization experiments reported by Koch, Schutz, 

Neufeld, and Mieszner. 

















Days 














Davs 




Days 


be- 






No. 

of 

calf. 


Weight 
of calf. 


Kind of 
ba('illus 
injected. 


Dose 
first in- 
jection. 


be- 
tween 
first 
and 
second 
injec- 
tions. 


Dose 

second 
injec- 
tion. 


be- 
tween 
second 

and 
control 
injec- 
tions. 


tween 
con- 
trol in- 
jection 
and 
death 
or end 
of test. 


Gain in 

weight 
during 
experi- 
ment. 


Result of final exami- 
nation. 








Centi- 




Centi- 












Pounds. 




grams. 




grams. 






Pounds. 




1 


359.7 


Human... 


o 


27 


5 


42 


100 


166.1 


Healthy. 


2 


353. 1 


do.... 


1 


27 


5 


42 


96 


39. C 


Lung tuberculosis. 


3 


326.7 


do.... 


2 


26 


5 


42 


100 


249.7 


Tuberculosis of serous 
membranes and kid- 
neys. 


4 


449.9 


do.... 


1 


26 


5 


42 


98 


159. 5 


Do. 


5 


346. 5 


do.... 


2 


,32 


6 


37 


100 


141.9 


Healthy. 


6 


■ 260.7 


do.... 


1 


33 


5 


36 


30 


58.3 


Miliary tuberculosis. 


7 


376. 2 


do.... 


9 


34 


5 


93 


246 


470.8 


Still alive. 


8 


289. 3 


do.... 


i 


30 


5 


93 


236 


529.1 


Healthy. 


9 


354.2 


do.... 


2 


49 


5 


90 


221 


371.8 


Do. 


10 


309.1 


do.... 


1 


49 


5 


90 


221 


427. 9 


Still alive. 


11 


330. 


do.... 


2 


50 


5 


90 


220 


451.0 


Do. 


12 


321.2 


do.... 


1 


63 


5 


88 


209 


272.8 


Healthy. 


13 


338.8 


do.... 


1 


52 


5 


88 


209 


178.2 


A tubercular focus the 
size of a hazelnut in 
the lung. 


14 


290.4 


do.... 


1 


44 


5 


88 


209 


215.6 


Healthy. 


15 


220.0 


do.... 


2 


54 


6 


91 


194 


308.0 


Tubercular foci in the 
lungs. 


IB 


270.6 


do.... 


1 


54 


5 


91 


194 


422.4 


Still alive. 


17 


220.0 


do.... 


2 


39 


5 


87 


184 


316. 8 


Healthv. 


18 


264.0 


do.... 


i 


39 


5 


87 


194 


312.4 


Still alive. 


21 


250.8 


do.... 


3 


103 






117 


217. 8 


Pleuritis and peritoni- 








tis villosa. 


22 


297. 
235. 4 
325. 6 

228.8 


do.... 

do.... 

Bovine ... 
do.... 


2 
1 

2 

1 


103 
103 
169 
169 






127 
119 
91 
91 


323. 4 
255. 2 
473.0 
310.2 


Pleuritis villosa. 


23 






Healthy. 


24 






Still alive. 


25 






Pleuritis chronica vil- 








losa, bronchitis and 




















peribronchitis ca- 




















tarrhalis chronica lo- 




















bularis. 


26 


321. 2 


do.... 


1 


21 






91 


354.2 


Bronchitis catarrhalis 








lobularis. 



Each two calves, from No. 1 to No. 18, inclusive, were vaccinated with human 
bacilli of a different stock and consequently calves 1 and 2 constitute one experi- 
ment, calves 3 and 4 a second experiment, and so on. With calves 1 to 6 the period 
between the last vaccination with human bacilli and the control inoculation was 
about forty days, and this the authors think was too short and jjartly accounts for 
these experiments being less successful than the others. They also express the 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 69 

opinion from the results of the experiments with calves 1 and 2 and 5 and 6 that 2 
centigrams of culture for the first vaccination causes a more rapid development 
of immunity and makes this immunity more perfect than does 1 centigram. There 
was very little difference between calves 3 and 4; both developed tuberculosis with 
lesions of the same character. Contrasting strongly with the above animals are the 
calves from 7 to 18, inclusive, which were not inoculated with virulent bovine 
bacilli until three months had elapsed after the last vaccination with human bacilli. 
All of these animals remained healthy with the exception of two, which showed 
comparatively insignificant remains of old tubercular lesions. The only symptom 
which these animals presented was slight fever, lasting from three to five days. 
They developed well and increased in weight. Seven of the calves had been dis- 
sected after being held about a year, and with calves 8, 9, 12, 14, and 17 not the 
slightest appearance of tuberculosis was discovered by very careful examination. It 
was only with calves 13 and 15 that such appearances were seen, and these were of 
old standing and probably recovered cases. The five calves still living, Nos. 7, 10, 
11, 16, and 18, are in excellent condition and free from any appearance which would 
lead one to suspect the existence of tuberculosis. 

These investigators conclude that by the use of human tul)ercle bacilli in the man- 
ner describecl by them a high degree of immunity may be produced in cattle, but 
that a considerable time elapses before this immunity develops to the highest point 
and that the dose of the culture used in the first vaccination has a notable influence 
upon the rapidity with which the immunity is acquired. All of the stocks of bacilli 
used by them were capable of producing immunity, the only difference being that 
some of the stocks affected the calves more seriously than did others, and young 
cultures produced fever of longer duration than okler cultures. The attenuated 
bovine bacillus, which was of sliglit virulence for cattle, produced immunity in the 
same manner as the human bacillus. 

The animals above refei'red to, Nos. 1 to 18, were immunized by two vaccinations 
with bacilli of human tuberculosis. The second vaccination, however, had produced 
only a slight reaction and this led the investigators to believe that perhaps a single 
vaccination with a proper dose of human tubercle bacilli might cause with cattle a 
sufficient degree of immunity. In order to test this question the investigators chose 
a culture for the vaccination which in former tests had produced a moderately strong 
reaction, and vaccinated by intravenous injection calf 21 with 3 centigrams, calf 22 
with 2 centigrams, and calf 23 with 1 centigram of a thirty-day culture. The general 
condition of the animals was not disturbed, and one hundred and three days later 
their immunity was tested l)y the injection of 2 centigrams of a culture of virulent 
bovine tubercle bacilli. Following this inoculation the animals had fever of several 
days' duration, and after its su])sidence appeared entirely healthy. After a period 
of one hundred and seventeen to one hundred and twenty-seven days the three ani- 
mals were all killed and examined, and proved to be entirely free from tubeiTulosis. 
These three calves had therefore developed a very high degree of immunity from a 
single vaccination with 1, 2, and 3 centigrams of the bacilli of human tuberculosis. 

A similar result was obtained with calves 24 and 25, which were vaccinated intra- 
venously with 2 centigrams and 1 centigram, respectively, of an attenuated stock of 
bovine l)acilli, and one hundred and sixty-nine days later were tested by inoculation 
with the very virulent bovine l)acillus. Calf 24, which had remained in an excellent 
condition, was still living. Calf 25 was killed and examined the two hundred and 
sixtieth day of the experiment, and, although affected with pleuritis chronica villo.'^a, 
bronchitis, and peribronchitis catarrhalis chronica lobularis, no tubercle bacilli could 
be found. 

The authors conclude that they have succeeded by a single vaccination with 1 to 3 
centigrams of bacilli of human tuberculosis or of attenuated bacilli of bovine tuber- 
culosis m producing in cattle an immunity against highly virulent bacilli of bovine 
tuberculosis. The bacilli as used up to this time and grown upon glycerin bouillon 
must be from 30 to 40 days old. They are dried between blotting paper, and the 
required amount is mixed with 10 c. c. of physiological salt solution and injected 
into the veins. 

vallee's experiments. 

On the initiative of M. Rossignol, and under the au.spices of the 
Societe de Medceine Veterinaire Pratique, there was be^un at Melun, 
in December, 1904, a series of experiments"" on the antituberculous 
vaccination of young cattle by the method of Professor Von Behring, 
of Marburg-. 



70 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

These experiments, which were conducted under ,the direction of 
Professor Vallee, had for their object — 

(1) To demonstrate the innocuousness of the method of vaccination. 

(2) To verif}^ the efficaciousness of the method. 

(3) To establish its practical value and in particular the duration of 
the immunity. 

December 5, 21 calves 4 to 6 months old were tested with tul^erculin without react- 
ing, and were held in places free from all contamination other than was received in 
the experiments. 

December 11, they were given the first vaccine in the jugular. 

About two months later one of the treated animals w^as attacked with "maladie 
des pulpes" and died. Its organs, examined by MINI. Moussu and Vallee, revealed 
no indication of the existence of tuberculosis. The other animals remained in per- 
fect health and showed normal development. 

February 1.3, the 20 surviving animals were tested with tuberculin. Four animals 
reacted clearly, with regard to which Professor Vallee remarked that the reaction 
was no cause "for anxiety or surprise, as the inoculated bacilli could not be absorbed 
without causing the formation of microscopic lesions sufficient to cause a reaction. 

March 12, three months after the first vaccination, the 20 animals received the 
second vaccine. 

At the beginning of June all vaccinated animals were tested with tuberculin. 
Only 1 animal reacted, and this failed to react to subsequent tests. This and 4 
other vaccinated animals were put in a lot together with the object of testing the 
duration of the immunity. 

June 15, the 15 vaccinated animals remaining were tested as follows: Six received 
4i milligrams each of a fresh culture of very virulent bovine bacilli; 7 were inocu- 
lated subcutaneously, and 2 were exposed by cohabitation with tuberculous bovine 
animals. Check animals which did not react to tuberculin and equal in number to 
the vaccinated ones were submitted to the same test. 

Very soon a number of the check animals showed very marked symijtoms, and 3 
of those inoculated intravenously died in thirty to forty days. 

The following is a brief resume of the results of these tests: 

A. Intravenous Tests. — {1) C]teckf<. — Three died with considerable pulmonary 
lesions thirty to forty days after the inoculation. The 3 surviving ones showed on 
autopsy extensive and generalized lesions. 

{2) Vaccinated animciis. — Five were absolutely immune. The sixth, affected with 
pasteurellosis at the time of the test inoculation, and consequently having less resist- 
ance, presented five or six disseminated tubercles in the bronchial and mediastinal 
glands, but no visceral lesions. 

B. Subcutaneous Tests. — (1) Check)^. — Three showed enormous lesions of the cor- 
responding prescapnlar gland. Four had in addition generalized lesions of the lungs 
ancl of the bronchial and mediastinal glands. 

(,?) Vaccinated animals. — With 5 of these no lesions were discovered in the glands 
nearest to the point of inoculation. With another there was found a tubercle in the 
prescapular gland. The seventh had an extensive tuljerculous adenitis of this gland. 

C. Tests by Cohabitation. — (i) Checks. — These had generalized tuberculosis fol- 
lowing an infection from the digestive tract, as was proved by the lesions observed. 

(^) Vaccinated animals. — These did not react to the tuberculin test and were pre- 
served and left in contact Avith tuberculous animals. 

Conclusions. — This method of vaccination appeared free from danger because none 
of the vaccinated animals reacted to tubercuHn a few months after the second vac- 
cination. As to the efficaciousness of the vaccination, it was shown that 5 out of 6 
of the vciccinated animals developed no lesions when tested by intravenous inocula- 
tion, whereas the checks died or became tuberculous; 5 of the 7 tested by subcu- 
taneous inoculation were immune, whereas the checks all had extensive lesions in 
the neighboring glands and several had generalized lesions in the lungs and annexed 
glands; and, finally, all of the vaccinated animals successfully resisted the test by 
cohabitation, which is the usual method of infection, whereas the check animals all 
became tubei'culous. 

Vallc'e concludes that it is experimentally possible to confer on young bovine ani- 
mals a high degree of immunity in regard to tuberculosis. The duration of the 
immunity is being tested by further observation. 



MATERfAL FACTS CONCERNING TUBERCULOSIS. tl 

CONCLUSIONS REGARDING IMMUNIZATION. 

It is evident from the investigations which have just been reviewed 
that great progress has been made in the development of a method for 
immunizing cattle against tuberculosis. The results of the different 
tests up to this time have not been as uniform as is desirable, but they 
are constantl}' improving in this respect, and there is good reason to 
expect that a safe and effective method will soon be available. At pres- 
ent there is considerable uncertainty as to the period of time during 
which the efficacy of the ""vaccine" remains unimpaired, as to the 
proper degree of virulence for the vaccine and the number of doses 
required for protection against natural infection, and also as to the 
duration of the immunit3\ 

The danger to the operator from using dr}^ and powdered human 
tubercle bacilli as vaccine has been mentioned by several investigators 
and should receive serious consideration. The liquid form appears to 
be more efficacious and more simple in its manipulation. The dry 
vaccine is said to retain its properties unimpaired for a month, l)ut 
considering the time required to put it in packages and ship it from 
Germany to the United States, it is to be feared that in many cases 
nmch more than a month would elapse between its preparation and its 
injection into American cattle. 

This method of protecting cattle from tuberculosis is still so new, 
and has ])een used so little under practical conditions, that it should 
only be adopted by the cattle owner with much caution and under 
expert veterinary supervision. The danger of adopting hasty conclu- 
sions as to the degree of innnunit}" conferred upon cattle by inoculation 
with tubercle bacilli has been shown by some of the experiments which 
have been mentioned in preceding pages. There is still much to learn 
about these " vaccines" and their effects, and the owner of cattle will 
be wise to avoid their use pending further investigations, except in 
the most urgent cases and under conditions where such treatment is 
clearly indicated. 

THE CURATIVE EFFECT OF TREATMENT WITH TUBERCULIN 
AND WITH ATTENUATED TUBERCLE BACILLI. 

Pearson and Gilliland''' have published a report of some experiments 
made by them to test the effect of treatment with tuberculin and with 
tubercle bacilli of the human typt^- upon young cattle which had 
reacted to tuberculin and which were presumably affected with tuber- 
culosis in its early stages. In testing with tuberculin a large herd of 
Shorthorn and grade Shorthorn cattle in December, 11>()2, it was found 
that practially all of the members of the herd responded to the test. 
Among the animals so responding were 12 calves from 6 to 8 months 
of age. These calves were obtained for use in this experiment and 
were again tested Februaiy 2-3, 1903. All responded to the test. 



72 TUBEECULOSIS OF THP: FOOD-PEODUCING ANIMALS. 

They were then weighed and divided into two lots of 6 each, as nearly 
equal in respect to size, weight, age, and condition as possible. One 
of these lots was subdivided into two groups of 3 each. 

The calves of one of these subgroups were given 7 intravenous injections of a 
standard suspension in water of tubert'le bacilh of human type. The dosage began 
at 1 c. c. and was increaseil to 6 c. c. The intervals were six to twenty days, and the 
period covered was from February 9 to May 1, 1903. A final injection was given 
about a year later, March 29, 1904. 

The 3 calves of the second subgroup were given subcutaneous injections of tuber- 
culin at intervals of from one to ten days. The injections of tuberculin were 
repeated until the hypersensitiveness of the animal to tuberculin had disappeared, 
after which the calves received an intravenous injection of a suspension of tubercle 
bacilli in water. Following each intravenous injection of living tubercle bacilli the 
animal was given tuberculin a number of times until its hypersensitiveness to tuber- 
culin again disappeared. The period of treatment extended from February 9 to 
April 30, 1903, inclusive, and the calves of this group, as of the group first described, 
were given an intervaneous injection of 5 c. c. of standard suspension of living 
tubercle bacilli March 29, 1904. Following this, tuberculin was administered five 
times at intervals of three or four days. 

The remaining 6 calves were given no treatment whatever, but were at all times 
kept with the 6 calves under treatment, so that all of the 12 calves in this experiment 
were subjected to the same conditions of life and subsisted upon the same kind and 
quantity of food. 

Two cattle, both controls, died; the first one May 5, 1903, the second September 
13, 1904; two — 1 control and 1 treated — were killed April 4, 1904, and the rest were 
killed in Septemljer, 1904. All were suljmitted to careful post-mortem examination. 

The calves of the first group had from one to three small tubercular lesions each, 
which were the size of a pea or less. In the case of one calf only was one of these 
found in the lung; in the others they were confined to the lymi^hatic glands. The 
calves of the second group had still smaller and more insignificant lesions, confined 
in all t'ases to the bronchial glands. In both of these groups of animals the lesions 
were cjuiescent, encapsulated, and some of them calcareous. The calves of the third 
group, which received no preventive treatment, were affected in a nuich more serious 
manner. In 4 of the 6 the lungs were quite extensively diseased; in 2 only were the 
tubercular changes confined to the lymphatic glands. One of the animals jiresented 
a case of "pearl disease" in its most advanced form and widest distribution. There 
was consequently a decided difference between the 6 young cattle that were treated 
and the 6 that were not treated; and since the two lots of animals were comparable 
in every way, excepting in respect to the specific treatment, it appears reasonable to 
conclucle that the treated animals were favoral)ly influenced by the treatment. Not 
only does the disease appear to have been held in check by the treatment, but there 
was reason to believe that in some of the animals it had a decided curative effect. 

In all of the treated animals the lesions were quiescent and. encapsulated, but they 
nevertheless contained living tubercle bacilli which were capable of causing the dis- 
ease in guinea pigs. The investigators remarked with reason that these experiments 
which were made on a few young cattle in the earlier stage of tuberculosis do not 
justify conclusions or inferences as to the probable effect of similar treatment on 
older and more extensively diseased animals. 

These experiments confirm the results of experiments by various 
investigators as to the production of inmiunity by the treatment of 
cattle with tuberculin and cultures of human and other tubercle bacilli 
nonvirulent for these animals. As to whether it will be advisable to 
administer such treatment to diseased young cattle in general practice 
must be considered doubtful, in view of the fact that the diseased areas 
continue to harbor virulent living bacilli for a long time after the treat- 
ment has been concluded. Further studies of this subject must be 
made before positive recommendations can be offered; but even with 
doubt on this point, the experiments have much value as indicating 
how complete a degree of immunity may be developed by proper 
treatment. 



MATEEIAL FACTS CONCERNI'N'G TUBERCULOSIS. 73 

ANIMAL TUBERCULOSIS AND THE PUBLIC HEALTH. 

EARLY YIEWS. 

There has been much difference of opinion as to the effect of animal 
tuberculosis upon the public health, and curiously enough the weight 
of numbers appears to haYc been with those who belieYed that there 
was little if any danger to be apprehended from this source. There 
were local laws in Munich more than five hundred years ago which 
prohibited the use of the flesh of animals affected with boYinc tuber- 
culosis, and similar ordinances were subsequently enacted in various 
German cities. There appears, however, to have been no great effort 
to enforce these ordinances, or, at most, they were only enforced spas- 
modically, until in the early part of the eighteenth century, when the 
opinion l^ecame prevalent that tuberculosis and syphilis W(>re identical. 
While this idea was dominant the regulations concerning the sale of 
the meat of tuberculous animals were more stringently enforced. 

In 1783, however, the health authorities of Berlin pronmlgated an 
opinion to the effect that tuberculosis and S3^philis were different and 
distinct diseases, and permitted the sale of the carcasses of tuberculous 
animals for human food. This view appears to have been accepted by 
other German States and by Austria, and for a third of a centur}' 
such meat was sold without c^uestion. The ideas in regard to tuber- 
culosis were vague and erroneous, and it was not until 1811 that 
Laennec proclaimed the unity of the different forms of tuberculous 
lesions. His views were vigorously contested, but they nevertheless 
made a strong imprfjssion upon the medical thought of the early part 
of the nineteenth century. Within a few 3' ears regulations were 
formulated in different places for the guidance of meat inspectors in 
judging the carcasses of tubercular animals. Gurlt (1831) recognized 
the tubercular nature of the " pearl disease'' of cows. 

About 1850 German histologists contested the views of Laennec and 
denied any relationship between human and bovine tuberculosis. 
Reinhard, Virchow, and Niemeyer recognized a true tuberculosis 
characterized by the " gray granulation," and a caseous pneumonia 
resulting from postinflammatory degeneration (Nocard). However, 
Gerlach, Spinola, Fuchs, Forster, Leisering, and others declined to 
accept such views and produced observations to show the tuberculous 
nature of the "pearl disease" of cattle. 

In 1866 Villemin introduced a new epoch in the discussion of ques- 
tions relating to the nature of this disease by demonstrating the inocu- 
lability of tuberculosis not only from animal to animal within the 
same species, but from an animal of one species to an animal of an 
entirel}^ different species, and even from man to animals. 

Villemin's conclusions were soon confirmed by the results of experi- 
ments made by Chauveau, Gerlach, Giinther and Harms, and other 
experimenters. As late as 1880, however, Virchow insisted at length that 



74 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

essential anatomic and pathologic differences separated the tubercles of 
the pearl disease of cattle from those of consumption in man, and held 
that the existence of a virus in pearl disease had not been demonstrated. 
It required another epoch-making discovery, that of the BdcUliis 
tul)erculoHk by Koch, in 1882, to convince the medical world that tuber- 
culosis was a communicable disease, and that an identical bacillus was 
found in the tubercles of man and many different species of animals. 
This discoverv again attracted attention to the danger which might be 
connected with the tuberculosis of animals and led to more rigid 
enforcement of regulations to guard against any dangers which might 
threaten the public health through the sale of meat and milk from 
tubercular animals. 

IDENTITY OF HUMAN AND BOVINE TUBERCULOSIS QUESTIONED. 

Years passed, and it appeared tobcdeffnitely established that human 
and animal tu])erculosis were identical, when Theobald Smith published 
(18!»8) the results of a comparative study of bovine tubercle bacilli 
and of human bacilli from sputum, in which it was shown that the 
bacilli from these two sources differed to such an extent that they 
might l)e considered as distinct types. Not only was there a great 
difference in the virulence of bacilli from the two sources, but there 
were marked morphological and cultural differences shown by the 
bacilli. These conclusions were soon confirmed by Dinwiddle and by 
Frothingham. 

The observations were not entirely new, however, as Sidnej^ Martin, 
in his experiments for the British Royal Tuberculosis Commission of 
1895, had shown that sputum from man was far less virulent for ani- 
mals than was bovine tubercular material. It could not be said from 
these experiments that human tuberculosis was not communicable to 
cattle, but onl}^ that it was communicated with difticultv, and when it 
was communicated the disease remained localized and did not result 
fatally. Of 6 calves to which sputum was fed by Martin, 2 showed no 
lesions, 1 had 53, 1 had 63, and 2 each had 13 tubercular nodules in the 
intestines. In one of these animals the mesenteric glands were also 
affected. In Smith's experiments there were also small lesions in some 
of the animals witli which he experimented. 

In an address before the British Congress on Tuberculosis, held in 
London in 1901, Koch expressed very radical views as to the difference 
between human and bovine tuberculosis. He held (1) that human 
tuberculosis differs from bovine, and can not be transmitted to cattle; 
(2) that while the susceptibility of man to bovine tuberculosis was not 
yet absolutely decided, he was nevertheless at liberty to say that if 
such a susceptibility really exists the infection of human beings is but 
a very rare occurrence. He estimated the extent of infection ])y the 
milk and tlesh of tubercular cattle, and the ])utter made of their milk, 
as hardly greater than that of hereditary transmission, and he there- 



MATERIAL FACTS CONOERNING TUBERCULOSIS. 75 

fore did not deem it advisable to take an}" measures against it. He 

held that it was now possible to determine whether tubercular disease 

in the human subject was of human or animal origin. He said: 

All that is necessary is to cultivate in iwre culture the tubercle bacilli found in the 
tubercular material, and to ascertain whether they belong to bovine tuberculosis by 
inoculating cattle with them. For this purpose I recommend subcutaneous injection, 
which yields quite specially characteristic and convincing results. 

This unexpected announcement by so great an authorit}" aroused 
great interest and led to tremendous activity among investigators in 
all parts of the world. As a result of the problem being attacked hj 
many individuals and from different points of view the principal facts 
have already been ascertained and established. 

INVESTIGATIONS BY THE GERMAN COMMISSION. 

Koch announced in his London address that the German Govern- 
ment had already appointed a commission to make further inquiries 
on the subject. A preliminary report was made from this commission 
b}' Kossel in 1903. At that time the commission had tested T cultures 
of tuberculosis from cattle and hogs — 4 from cattle and 3 from hogs. 
Two of these cultures proved acutely fatal to cattle after eight to nine 
weeks. Four of the cultures likewise produced a generalized tuber- 
culosis, but which certainly had a more chronic course, while 1 of 
the cultures caused only an infiltration at the point of inoculation, 
Avith some caseous foci in the adjoining prescapular gland and in one 
of the mediastinal glands, and there was lacking the spreading of 
tuberculosis over the entire body, which they were accustomed tp see 
after the injection of cultures of bovine tuberculosis. "Hence,'' said 
Kossel, "among bovine tubercidosis bacilli there can also occur dif- 
ferences with regard to the virulence.'' 

The commission had also tested 39 different freshlj^ made cultures 
from tuberculous disease in man. Nineteen of these cultures did not 
produce the slightest symptoms in cattle; with 9 others the cattle 
exhibited, after four months, ver}^ minute foci in the prescapular 
glands, which were mostl}^ encapsuled and showed no inclination to 
progress; with 7 others there was somewhat more marked disease of 
the prescapular glands, but it did not go so far as a material spread- 
ing of the process to the glands next adjoining. There were 4 cul- 
tures, however, which were more virulent and caused generalized 
tuberculosis in the cattle inoculated with them. 

It was therefore evident that, contrary to Koch's assertion, it was 
not alwa3^s possible to determine whether a culture of the tul>erculosis 
bacillus originated in man or in cattle by inoculating it subcutaneously 
in bovine animals. One of the bovine cultures failed to produce gen- 
eralized tuberculosis in cattle, which according to Koch's contention 
it should have done; and 4 of the human cultures did produce this 
form of disease, which according to the same authority they should 
not have done. Moreover, wiiile some of the human cultures caused 



76 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

no disease at all, others led to the development of minute foci in the 
prescapular glands, and still others to somewhat more marked disease 
of these glands. There were, consequently, four degrees of virulence 
noted in these 39 cultures from human sources, and three degrees of 
virulence in the 7 cultures from animal sources. 

It was definitel}^ admitted that 4 of the human cultures caused gen- 
eralized tu])erculo8is in cattle; but it was suggested by Kossel that it 
might be possible that the bacilli in cases of human tuberculosis under 
certain circumstances could likewise attain a very high degree of 
pathogenic activity for cattle without being for that reason bovine 
bacilli. The German commission was confronted by the two horns of 
a dilemma, either one of which was fatal to the views of Koch as 
stated with great positiveness at London. If the suggestion thrown 
out by Kossel was adopted it was necessary to conclude that Koch was 
wrong in his claim that human tuberculosis can not be transmitted to 
cattle, and thus with one stroke of the pen the commission would 
destroy the entire experimental support which he had for his argument 
before the British Congress on Tuberculosis. If, on the other hand, 
it accepted the conclusion which followed from the principle laid down 
b}' Koch for discriminating between human and bovine bacilli, it was 
necessary to admit that bovine tuberculosis is an extremely important 
factor in the etiology of human tuberculosis. Of the 39 cases of 
human tuberculosis tested, 4, or over 10 per cent, were virulent for 
cattle and would be classified as of bovine origin; but these 4 cases 
were all found among the 16 cases of tuberculosis in children wdiich 
the commission investigated; and, therefore, 25 per cent of the cases 
tested of tul)erculosis in children should by Koch's method be classified 
as of bovine tuberculosis. 

These results were in accordance with researches made by other 
investigators. De Schweinitz, Mohler, and Ravenel in this country 
easily succeeded in obtaining human tubercle bacilli which caused 
generalized tuberculosis in cattle, and most of these originated in 
tuberculous children. 

INVESTIGATIONS BY THE GERMAN IMPERIAL HEALTH OFFICE. 

In 67 cases of tuberculosis in human l)eings studied up to the present 
time in the investigations of the German imperial health office,"^ and 
which were selected with the object of finding as many cases as pos- 
sible of the bovine type, there were found in 56 cases bacilli of the 
human type alone, in 9 cases bacilli of the bovine type alone, and in 
2 cases bacilli of both types were found in the same person. The 9 
cases affected with bovine bacilli alone were all children under 8 years 
of age. Of the 2 persons affected with bacilli of both types one was 
a woman 30 years old and the other a child 5k 3^ears old. 

Eleven cases of tuberculosis in fowls were investigated, all of which 
were caused by the fowl tuberculosis bacillus. In 11 different cases 



MATERIAL FACTS CONCERNING TUBERCULOSIS. 77 

of tuberculosis in cattle there were found exclusively bacilli of the 
bovine type. In 7 cases of tuberculosis in swine there were found 
only bacilli of the bovine type. In one case in a 3-months-old pig 
which had shown no S3miptons of tuberculosis there were found fowl 
tuberculosis bacilli in the caseous mesenteric glands. In one case of 
general tuberculosis in a sheep there were found tubercle bacilli of 
the bovine t3^pe. 

" The German imperial health office ''' has recently given out the fol- 
lowing summar}^ of the results of the investigations relative to the 
danger to human health from animal tuberculosis: 

1. Tuberculosis OP Domestic Animals. — A. Tuberculosis of cattle. — 1. Bovine tuber- 
culosis is caused by tubercle bacilli of the ti/jms bovinus {ho\ine type). It arises 
through infection with tubercle bacilli which have been excreted by diseased ani- 
mals suffering from certain forms of tuberculosis. 

2. The source for the infection of cattle is almost exclusively cattle which are suffer- 
ing from tuberculosis of the udder, of the intestines, of the uterus, or of the lungs, 
and which excrete tubercle bacilli with the milk, with the contents of the intestines, 
with the secretions of the uterus, or simply through the respiratory organs. 

3. The sickening of cattle is possible in consequence of the reception of tubercle 
bacilli of the typus bovinus which have been excreted by other diseased domestic 
mammals such as sheep, goats, and swine suffering from tuberculosis. 

4. The tuberculous human being, in the rare cases in which he excretes tubercle 
bacilli of the typiis bovimis, presents danger to cattle. 

5. The tuberculosis of fowls seems, under ordinary circumstances, hardly to present 
any danger for cattle. 

6. In combating tuberculosis in cattle the most important thing is to prevent the 
transference of the germs of infection from tuberculous to sound cattle. 

B. Tuberculosis of swine. — 1. In tuberculous swine, tubercle bacilli of the typus 
bovinus are almost without exception the only ones found in the disease centers. 

2. Tuberculosis of swine has its principal origin in the tul)erculosis of cattle, and 
in the second place in the transference of tuberculosis from one hog to another. Nor 
is it impossible for the tuberculosis of other domestic mammals and of fowls to be 
transferred to swine. 

3. The tuberculous human being can give tuberculosis to swine, no matter what 
be the origin of his own disease. 

4. As source of infection, the excretions and the flesh of diseased mammals in which 
living tubercle bacilli are contained come chiefly under I'onsideration. The greatest 
danger comes from feeding swine with the sei)arator refuse from the dairies. 

C. Tuberculosis in the other domestic niaminals. — 1. The tuberculosis of the other 
domestic mammals is to be traced back in most cases to the tuberculosis of cattle. 

2. It is to be expected that the repression of the tuV)erculosis of cattle will lead to 
a decrease of the tuberculosis of swine and the other domestic mammals. 

D. Tuberculosis in domestic birds. — 1. The tuberculosis of domestic birds (fowls, 
pigeons, ducks, and geese) is generally caused and spread by the fowl tuberculosis 
bacillus. 

2. As the principal source of infection we must consider the intestinal excretions 
and parts of the bodies of diseased birds which have undergone tubercular changes. 

II. TuBEKCULosis OF HuMAN Beings. — 1. In parts of the humau body affected by 
tuberculosis there are generally found tubercle bacilli of the typus humanus (human 
type) . 

2. It must be assumed that here the infection with tuberculosis has taken place 
chiefly through direct or indirect transference of tubercle bacilli from man to man. 

3. Accordingly the measures recommended for combating tuberculosis are directed 
principally against the direct or indirect transference of the germ of infection from 
tuberculous to healthy people. 

4. Besides this we must reckon with the possibility that tubercle bacilli of the 
typus Jiumanus may be transferred to human beings through the flesh of tuberculous 
swine. 

5. The fact that in a number of cases where organs of the human body have been 
found to have undergone a tuberculous change, the presence of tubercle bacilli of the 
typus borinus has been proved, shows that the human body is capable of receiving 
the germs of infection from secretions containing tubercle bacilli (for example, milk) 
or from tuberculous flesh of domestic mammals. 



78 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

6. The changes in the tissue brought about in human beings through tubercle 
baeilh of the iypus bovinm are hmited in a remarkable number of cases to the passage 
through which the germs have found entrance, and to the adjacent glands or to the 
latter alone. Nevertheless tubercle bacilli of the typus horhnis have also been found 
in cases where the disease had spread from the locality of entrance to distant parts 
of the body and had caused the death of the person in question. 

7. Tlie use of food, therefore, which conies from tuberculous animals and contains 
living tubercle bacilli of the typus bovinus is not to be regarded as being without 
danger for the health of human beings, esj>ecially when the latter are children. 

8. A conscientiously conducted meat inspection constitutes an important protection 
against the transmission of the tubercle l)acilli to human lieings through meat; there 
is also protection afforded l)y the proper preparation of meat (thorough lioiling or 
roasting). 

9. The possibility of the transference of tubercle bacilli through milk or milk 
products to the human being may be consideral)ly diminished by the efficient com- 
bating of tuberculosis in cattle. The tubercle bacilli contained in milk may be killed 
by heating the milk to the necessary temperature. 

" 10. The tuberculosis in poultry used for domestic purposes appears to play no part 
in the propagation of the disease among human beings. 

CONCLUSIONS NOW GENERALLY HELD BY SCIENTISTS. 

These statements fairly represent the condition of our knowledge 
with reference to human and animal tul)erculosis, but the conclusion 
should not be reached from this ])rief sununar}^ that the German 
investigators are entitled to all the credit for having elucidated this 
perplexing question. On the contrar}^ similar results were announced 
at an earlier date b}*^ the investigators of other countries, and especially 
by those of (jreat Britain, France, and the United States. 

The following conclusions are, therefore, regarded as demonstrated 
b}" experimental investigations in which many scientists have partici- 
pated, and these conclusions are noAV generally accepted by scientific 
men: 

1. Bovine tuberculosis may be comnumicated to human beings, and 
in such cases it is usually children that are all'ected. 

2. Tuberculosis of other domesticated mammals (hogs, sheep, goats, 
etc.) may also be communicated to human beings. It is usuall}", but 
not always, of the bovine type. 

3. The tuberculosis of poultry is not communicable to himian 
beings. 

4. Parrots and some other varieties of cage birds may be affected 
with a type of tuberculosis communicable to human beings. 

5. The tuberculosis of human beings, as a rule, is not communical)le 
to cattle, but is communicable to pigs, dogs, and cats. The bacilli in 
a certain proportion of the cases of human tulierculosis, however, are 
virulent for cattle and produce in these animals a fatal generalized 
tuberculosis. 

6. Precautions should be taken to protect human beings from animal 
tuberculosis by a careful inspection of meat-producing animals at the 
time of slaughter and of the cows from which milk, cream, and butter 
are produced. 



PART II.— THE REPRESSION OF TUBERCULOSIS. 



MEASURES THAT MAY BE ADOPTED BY INDIVIDUALS. 

PREVENTION Bi' AVOIDING KNOWN CLAUSES OF TUBERCULOSIS. 

The first requisite for preventing- tul)ereulosis is to provide roomy, 
well ventilated, light, dry, and clean stables for the animals. Tuber- 
culosis will not originate even in dirty stables if the bacillus is not 
introduced in some manner; but there are so many ways by which it 
may enter a stable that the l)reeder and daiiyman should always be 
prepared for it. There is much less danger of the disease spreading 
in a stable properly built and maintained than in an ordinary stable, 
and in case it spreads, its progress will be much slower, and the 
animals less severeh^ afl'ected. 

There are a few points in the })uilding of a stable to make it as secure 
as possible against tuberculosis which should receive special attention. 
It is preferable that the Hoor should be of concrete. Wooden Hoors 
are generally defective and allow liquid or even solid matter to work 
through them and collect in the space between double Hoors, or under 
the stable, creating in time a foul, fermenting mass of organic matter 
which keeps the stable damp and filled with noxious gases. In the 
disinfection of stables for pleuropneumonia and foot-and-mouth 
disease, the writer saw examples of tilth between and under floors, 
even on good dairy farms, which has made him partial to concrete. 
And yet it is possible to put a good wooden floor in a cow stable and 
to keep the stable in a good sanitaiy condition. 

The stables should have solid partitions separating complete!}' the 
mangers and the greater part of the stalls. Tul)erculosis is very apt 
to spread from animal to animal in the order in which the}' stand in 
the stable. The infection occurs through the small particles of nuicus 
or of tuberculous material which are forcibly expelled into the air when 
an afl'ected animal coughs, or through the saliva which soils the man- 
gers or drinking vessels, or through the animals touching noses or 
licking each other, A solid partition as high as the animals' backs 
guards against such infection and does much to limit the spread of the 
contagion. 

The method of watering also has considerable influence on the spread 
of tuberculosis. It is quite conmion to have a long trough in front of 
a row of stalls which extends the length of the row and is filled with 
water from one end. As the water runs into this trough it passes in 
front of every cow in the row and carries with it saliva or tuberculous 

79 



80 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

material which may have been deposited anywhere along- its course. 
The last cow in the row receives water that may have been contami- 
nated by an}^ other cow in the row; and ever}^ cow in the row except 
the first one receives the washing-s from some other cow's manger. 
So long as the cows are all in good health this makes little difference, 
but if a tuberculous cow with virulent saliva is stabled in such a row 
the infection of the other animals in the stable is greatly facilitated. 
An individual drinking basin so arranged that the water is automat- 
icall}' kept at a certain level, or a common trough in the open air and 
sunshine which has running water and from which the surplus water 
is removed at the surface, is to T)e preferred. 

Any kind of material may be used for the walls of the stable, but 
the inner surface should be as free from projections and as smooth as 
possible. The object should be to secure a wall that is easily cleaned 
and that has few cracks and projections to hold dust and dirt. 

The amount of air space required per cow depends upon the effect- 
iveness of the system of ventilation. In a stal)le with a commodious 
passageway in front and back of the cows, and witli a free space over 
the partitions of the stables reaching 9 or 10 feet above the floor, there 
will be space enough if the air is renewed as it should be. There are 
different methods of ventilation availaljle by which this ma}" be accom- 
plished without producing injurious drafts upon the animals, and 
the one should ])e selected which appears most suitable to the kind of 
structure that is to be erected. 

A matter of some importance is to keep the cattle in the open air as 
much as possible. Not only does this improve the vigor of the animals 
and enable them better to resist infection, but there are fewer chances 
of infection at pasture or in open pens than there are in stables. The 
plan of keeping the cows in stables only at milking time in winter and 
of turning them into an open shed during the remainder of the time 
is to be recommended, except in very severe weather. 

There should also be special attention given to food which is liable 
to be contaminated with tuberculous infection. The young calves 
should be given the milk of cows known to be healthy, or, in case this 
can not be done, the milk should be sterilized. Sterilization should 
also be practiced with skim milk fed to both calves and pigs. Hay 
contaminated with the dust from stables inhabited by tuberculous cattle 
is dangerous for healthy animals. 

The most essential precaution to be observed to prevent the intro- 
duction of tuberculosis is to take proper measures to see that any cattle 
brought upon the premises are free from the disease. Such animals 
should he tested with tuberculin, but this alone may not be sutficient. 
Cattle which have been previously tested often fail to react to the 
tuberculin test even when they are affected with tuberculosis, conse- 
quently the herd from which the animals are to be purchased should 



THE REPKESSION" OF TUBERCULOSIS. 81 

be examined as a whole, and if any members of it show signs of tuber- 
culosis it is not safe to receive animals from that herd. 

It should be remembered that tuberculosis is a very connnon disease, 
especially among dairy cattle, and that it is a difficult matter to add new 
animals frequently to a herd and at the same time avoid the introduc- 
tion of this disease. A herd free from tuberculosis should therefore 
be renewed and increased by its own offspring' so far as possible. To 
bring in animals from other herds, either temporarily or permanently, 
is to accept a risk that may prove disastrous. 

ERADICATION OF TUBERCULOSIS FROM THE FARM. 

If there is any reason to suspect the existence of tuberculosis in a 
herd, an effort should be made at once to determine definitel}^ whether 
it is present and which animals are affected by it. 

The general condition of the animal should furnish some indication. 
If any of the animals are not doing well, are losing flesh, and fail to 
yield the amount of milk which is to be reasonabl}^ expected, a careful 
examination should be made of them to determine whether their tem- 
perature is normal, whether there are signs of enlargement of the 
external lymphatic glands, and whether abnormal sounds can be 
detected in the lungs. The examination of the carcasses of any ani- 
mals which may have died or are slaughtered is a valuable indication 
as to the existence of the disease in the herd. 

The most reliable means of determining this question is, however, 
the tuberculin test. While this may occasionally fail to reveal tuber- 
culosis in an individual animal, it may be relied upon with certainty 
to reveal the existence of the disease in a herd. If this test indicates 
that some of the animals are tuberculous, measures should be at once 
adopted to eradicate the disease from the herd, or at least to prevent 
its further spread. In case there are only one or two animals affected, 
and these are not especiall}^ valuable, the best plan is to slaughter them 
at once and thoroughly disinfect the stable in which they have been 
kept, If a large proportion of a herd is affected, and the animals are 
not especially valuable, the best and cheapest plan would be to separate 
the reacting animals from the healthy ones, and to have the former 
slaughtered under inspection as soon as they can be put in proper con- 
dition. It is probable that the flesh of most of these ^nimals would 
be found fit for food, and the loss, therefore, would not be very great. 
In case the herd has been long affected and manj^ of the animals are in 
an advanced stage of the disease, they are unfit for milk production, 
and the sooner they are slaughtered the less will be the loss. 

If the herd contains animals which are valuable for breeding pur- 
poses, the Bang system of management or some modification of it may 
be profitably adopted. 

1881— No. 38—06 6 



82 TUBERCULOSIS OF THE FOOD-PRODUCIKG ANIMALS. 

The Bang Method of Eradicating Tuberculosis. 

What is generally known as the " Bang- method '' of eradicating tuber- 
culosis®* is entirel^v voluntary on the part of the owners and consists 
essentiall}^ in testing the entire herd with tuberculin and in isolating 
as completely as possible the animals which do not react and which 
show no physical signs of the disease, and also in isolating the calves 
from reacting cows and feeding them upon the sterilized milk of react- 
ing cows or upon the milk of cows which have not reacted. 

Jn making the tuberculin test it was found that in Denmark, where 
approximatel}" 50 per cent of the cows were tuberculous, 22 per cent 
of the herds tested were entirely free from this disease. In man}^ other 
herds but a few animals reacted, and it was often an easy matter to 
put such animals in a separate place until they could be sold. In those 
cases in which almost all grown-up animals reacted, while most of the 
young cattle were sound, it was often possible to place the latter in a 
particular stable for }■ oung cattle, as such a staljle may easily be made 
if it is not at hand. The greatest difficulty of isolation occurred when 
there were both a great many diseased and a great many sound cattle. 
In this case it was usually necessary to divide the stable by a solid 
partition. But not infrequently the construction of the stable was 
such that it was necessar}' to have doors in the partition to allow feed- 
ing or the removal of the manure. This arrangement did not prove 
to be a good one, as there was too nuich opportunity for contagion 
even if the doors were kept shut during the time they were not in use. 
In some cases good results were obtained even with such unsatisfac- 
tory stabling. When the sound animals were placed in completely 
isolated sta])les, and especially when these were in difierent buildings, 
the result was usually ver}' satisfactor}'. The best manner of isolation 
was found to be to place the animals upon another farm from that 
occupied Ijy those which reacted. 

It is not the intention by this plan to exterminate tuberculosis 
promptly, but to reduce it gradually and without great expense to 
the owner of the infected herd. 

If a stock of heavy milking cattle has been built up by ^ears of 
selection, or if the herd is purebred, the blood may be retained and 
the breeding operations continued without interruption. It is in such 
cases that the method has the greatest value. With ordinar}^ cows it 
would probably be to the financial advantage of the owner to estab- 
lish a clean stable for the nonreacting cows and for newly purchased 
ones, all of vvhich should of course be tested, and to turn oii' the 
reacting cows as soon as possible and without attempting to raise 
calves from them. 

In formulating the Bang method it was assumed that animals react- 
ing to tul)erculin but showing no evident clinical signs of tuberculosis 
are in the majority of cases affected but to a limited extent and that 



THE REPRESSION OF TUBERCULOSIS. 83 

therefore it i« not necessary to kill them. They may live and keep 
apparently healthy for years, their milk as a rule does not eontain 
tubercle bacilli, and by pasteurization every danger of contagion can be 
avoided. Their flesh, also, will generally be safe for food, and if killed 
under inspection the dangerous carcasses may be condemned. In the 
immense majority of cases such cows will produce healthy calves. 

Among the reacting cattle there will aiwa3's be some subjects in 
w^hich the disease develops, so that they become disseminators of con- 
tagion. The reacting animals must, therefore, be separated from the 
sound ones as thoroughl}^ as possible. The newborn calves must be 
immediately removed from the stable where the reacting cows are 
placed, and they must have boiled or pasteurized milk. The sound 
section should ])e tested with tuberculin at least once ever}" year, in 
order that the animals which have contracted tuberculosis in spite of 
the separation maj^ be removed. 

Writing with reference to two of the farms where this plan had Ijeen 
in operation several years. Professor Bang said that in spite of the 
separation every year several animals have fallen by renewed test of 
the sound division, some years very few, some years more. It can 
not be expected that every trace of the contagion will be excluded 
from the sound section when the two sections are near each other, 
since there are too man}^ opportunities for the contagion to be carried 
in various ways, as by people, dogs, cats, rats, etc, and perhaps also 
through food, as in Danish stables the common hayloft is usuall}- a])ove 
the stable. Where it has been possible to place the two sections in 
quite difierent buildings or on separate farms the results are usuall}' 
much better. 

A MODIFICATION OF THE BANG METHOD. 

Ujhelyi, **' of Hungary, at the last International Veterinary Congress 

referred to a modification of the Bang method which he had practiced 

with success in his country. 

The basis of the Bang method of tuberculosis suppression, he said, consists on 
the one hand in separation of those animals which respond to the tuberculin test 
from the others and on the other hand in artificial feeding of the calves with milk 
warmed to 80° to 85° C. In Denmark the artificial feeding was usual before, and 
the great number of dairy associations rendered it possible to return the skim milk 
pasteurized. The dairy associations in Hungary are, on the whole, smaller, and the 
purchase of pasteurizing machines can not be carried out; neither is it usual here to 
feed calves artificially. I have, therefore, while taking the Bang process as a basis for 
suppressive measures, adopted Hungarian conditions for its introduction upon sev- 
eral larger and smaller estates — that is, the expensive and complicated process of 
artificial feeding was abandoned and the calves given to be fostered by cows which 
did not respond to the test. When new drafts of cows arrived, the foster mothers 
were selected from these; if none could be found unresponsive to the test, the calves 
were fed by their own mothers, though these might be responsive; and care was 
taken meanwhile to allow the calves to l)e with their mothers only while feeding 
and to remove them from the cow house immediately after weaning. Of these calves 
fed of necessity, though under projier i)recauti()ns, by mothers responsive to the 
test, hardly more, on a yearly average, than 10 per cent were found to react, while 
of those fed by nonreacting foster mothers the numl>er reacting, on a yearly average, 
was 2 to 6 per cent — results that, even under the application of the original Bang 
process, could hardly have been bettered. At least, of the 10,533 young animals 



84 TUBEECULOSIS OF THE FOOD-PKODUCING ANIMALS. 

artificially reared and half-yearly examined upon the Archduke Frederic's estate at 
Magyar-Ovilr, 400 — i. e., 3.7 per cent — were found to react to the test, while, on the 
other hand, during my own researches of 7,296 young animals only 239, or 3.3 per 
cent, reacted. It is to be noted that the examinations on three out of eight estates 
took place every nine months. 

I lately had occasion to introduce and without much difficulty to apply the Bang 
process of suppression, especially in the form adapted to our peculiar conditions, not 
only to small establishments of some 70 head, but to places with a stock of 150 to 
250 and to large establishments of 400 to 700. But the process has also been applied 
here in its original form at IMezohegyes, for instance, on a farm of over 1,000 head, 
which was completely freed from the disease in four or five years; also, on the Mag- 
yar-Ov;tr estate, on a farm of over 5,000 head, where after five years' treatment 
three-fifths of the stock are free from tuberculosis. 

SUCCESSFUL TREATMENT OF A WISCONSIN HERD. 

Russell,*'" of the Wisconsin Agricultural Experiment Station, has 
given an interesting account of the successful treatment of an out- 
break of tuberculosis in a herd of cows in that State. The measures 
were carried out in accordance with advice received from the experi- 
ment station. 

Eight years before this account was written a thrifty farmer in one of the eastern 
counties of the State decided that he could have better cows than those which he 
then possessed. He did not sell all that he had and buy new ones to take the place 
of the old herd, 1)ut he purchased a few purebred animals tliat he had reason to 
believe were better milk producers than his own cows. With this influx of new 
blood he started, as thousands of dairymen have done, to "buildup" a herd by 
gradual selection of the best animals. 

When this purebred stock was first bought it was kept apart from the balance of 
the herd until three years later, at which time the herd was reclivided on a basis of 
age, all young animals being kept together on one side of the barn, while the mature 
animals were stabled on the other side. 

The following year some of the purebred cows began to fail, and within another 
year 2 of tliem died of what later was determined to be tuberculosis. The owner 
at this time was ignorant of the true nature of the malady, as the slow wasting away 
of the animals had not especially impressed him. When the character of the disease 
was ascertained by a post-mortem examination, a tuberculin test of the entire herd 
was at once made, under the auspices of the experiment station, and the surprising 
fact established that, with three exceptions (13 out of 16), all of the mature animals 
in the herd reacted. In addition to this, 3 head of young stock also responded to 
the test. 

Supposing that some of the original cows were infected with the disease at time of 
purchase, it is probable that tlie malady was disseminated among the mature animals 
from 1894 to 1896. In this brief space of time the outbreak had spread so that 
nearly every mature animal in the herd was more or less involved. This had 
happened practically unsuspected by the owner. 

Believing that in this case it was possible to restore the herd to a perfectly healthy 
condition and that it could be done with less expense than it would be to kill all the 
animals that reacted and fill their places with other stock, the following method was 
proposed to the owner and adopted by him: 

Separate at time of test all reacting from nonreacting animals, keeping them prac- 
tically as two independent herds. Breed these reacting animals under careful con- 
ditions, separating the calves at birth from their mothers, feeding them on thoroughly 
pasteurized milk of reacting cows (or milk from nonreacting animals). All healthy 
cows, and calves from both affected and healthy sections, to be kept in quarters 
known to be free from tuberculous contagion. The disposition of the product of the 
reacting herd may be varied to suit the exigencies of the occasion, but in any case it 
should l)e treated by pasteurizing so as to render it innocuous. 

The conditions were such as might be found on hundreds of farms. No other 
building was available in which either the healthy or the affected part of the herd 
could be kept, and it was therefore necessary to arrange quarters in the original 
stable so as to prevent contact of one section of the herd with another. This was 
done by throwing a partition made of a single thickness of boards across the stable. 
The two sections of the herd were pastured in separate paddocks and watered in dif- 



THE REPRESSION OF TUBERCULOSIS. 



85 



ferent tanks. It was somewhat hazardous to allow direct passage between the two 
compartments, and also to bring the food for the healthy section through the room 
occupied by the diseased stock, but such an arrangement under the circumstances 
was the only practical one that could be instituted. 

Before the rel)uilding of the herd was begun it was necessary to disinfect the whole 
stable thoroughly. All litter and loose material were first cleaned out, so as to give 
better penetration to the disinfectant; then the stalls and mangers were thoroughly 
washed with a hot solution of lye, the walls and ceilings being treated with a coat of 
milk of lime (a thin whitewash made from freshly slaked lime). 

The first test was made January 2, 1896. On January 10 the herd was divided into 
two sections, and from that time these divisions were handled as two separate herds. 
Various animals were disposed of from time to tin:ie, and a final test of the entire herd 
was made in February, 1899. The following table shows the results of the different 
tests made of the two sections of this herd: 

Actual condition of the lierd at times of different tests. 



Date of test. 



Tuberculosis sec- 
tion and its prog- 
eny. 



Healthy. Diseased 



Healthy section 
and its progeny. 



Healthy. Diseased 



January, 1896 . 

May, 1896 

April, 1897 .... 
December, 1897 
February, 1899 



In no case did any of the animals, originally pronounced tu]:)erculous, ever fail to 
react in any of the suljsequent tests. It is also remarkat)le that no case of disease 
appeared in the healthy section of the herd. One of the striking facts noted in these 
investigations was the May in which the disease progressed in the individual animals. 
By 1896, two of the original cows had died. Of the 16 affected when the first test was 
made, several were killed for demonstration purposes. In 1896 and 1897, four had to 
be destroyed on account of the progress of the disease; in 1898, two more broke down, 
and up to August, 1899, one more succumbed. 

It was noteworthy in those cases in which the disease gained the ascendency over 
the animal that the decline was generallj' rapid toward the last. The animal main- 
tained itself in good condition until some set of causes threw it from a chronic latent 
tuberculosis into an acute stage. The intense cold of the last winter hastened this 
change in one case; in two other instances the inciting cause was evidently the strain 
of calving. A fact of great practical value was that the diseased condition generally 
remained comparatively quiescent for a number of years, the resisting powers of the 
body being able to hold the disease germ in check; then a sudden turn for the worse 
occurred, generally as a result of some external inciting cause. 

ERADICATION FROM A CONNECTICUT nERD. 



The eradication of tuberculosis from the herd of the Connecticut 
Agricultural College^" is also an object lesson as to what may be 
accomplished b}' intelligent management of a tuberculous herd. 

The healthy and reacting animals were separated and placed in adjacent barns; 
they also had separate yards and watering places, and at no point did they ccjiiie in 
contact, except that the same service bulls were used for both herds. The barn in 
which the reacting herd was quartered was well ventilated and admitted consider- 
able sunlight. As little passing as possible was permitted. The attendants who 
milked, fed, and cared for the herds were instructed to wait upon the healthy herd 
first and later upon the affected herd, and only in this order. The milk from the 
reacting herd was pasteurized and used for butter making. The calves from this 
herd were removed when dropped and quartered with the healthy herd. 

In this case it was not practicable to remove the nonreacting animals to new quar- 
ters and leave the reacting animals in the old quarters, and therefore the old barn 
was thoroughly cleaned and disinfected with a 5 per cent solution of crude carbolic 



86 



TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 



acid. The fullowing table shows the gradual elinnnation of tul)erculosis from the 
herd : * 



Date of tuberculin test. 



December 28, 1898 

Mav22, 1899 

December 7, 1899., 

April 16, 1900 

November 24, 1900 

March 20, 1901 

February 17, 1902. 




Number 
of reac- 
tions. 



It is not known whether the reactions which occurred after the 
first test were due to too lax a quarantine, to an inefficient disinfection 
of the old barn, or whether they were incipient cases that developed 
later. The advisability of testino- once or twice a year is apparent. 

The successful and rapid eradication of the disease in the herd of 
the Connecticut Agricultural College shows that the arrangements 
were well made and the quarantine rigidly enforced. The results of 
this method are not alwaj's so favorable, however, as is shown by the 
following instance related by Regner *^^ as having been observed in the 
tuberculosis work in Sweden. 

RECOMMENDATIONS OF REr4NER, OF SWEDEN. 

In one locality the struggle against tuberculosis had been kept up 
for seven 3'ears in three herds with the result as shown in the table 
which follows: 



Year. 


Number 

of 
animals. 


Number 
reacting. 


Year. 


Number 

of 
animals. 


Number 
reacting. 


1897 


331 

197 
226 
286 


258 

39 

7 

14 


1901 


312 

391 
408 
416 


22 


1898 


1902 


15 


1899. . 


1903 


2 


1900 


1904 


83 









Of the animals reacting in 1904, 80 were in a stal)le where there 
were only 123 head of cattle. Upon investigating the cause of this 
remarkable increase in the number of diseased animals it was found 
that a cow which had reacted in 1897, but after that year had not 
reacted, and which had been left with the sound stock, had developed 
open tuberculosis (lung and laryngeal tuberculosis) during the last 
year and had stood a part of the time at each of the four feeding places. 

Regner is of the opinion that a herd of cattle seriously affected with 
tuberculosis should not be tested with tuberculin, but that such animals 
as show signs of the disease by other tests should be removed, and that 
sound stock should be bred from the apparently sound stock in the 
tuberculous herd. He gives the following rules, sup^^lementary to 
perfect isolation, infection-destroying treatment of milk food, and 
disinfection of cow houses, as deserving special emphasis: 



THE REPRESSION OF TUBERCULOSIS, 87 

1. That the old stock should from time to time be freed, by the use of clinical and 
bacterioscopic methods, from individual animals in which tuberculosis has shown 
itself. 

2. That the newborn calves of this stock should be immediately brought to the 
jjrotected stock. 

3. That the raw milk should be taken from the mother with such precautions that 
exterior infection of it should as far as possible be rendered impossible. 

4. That the calf should be tested as soon as possible with tuberculin — the first time 
when 8 days old, the second time when half a year old, and afterwards once a year. 

5. That every animal so tested and found to react should be marked to prevent 
mistakes in isolating, and that a clinical examination should be held upon any ani- 
mal whose appearance and behavior (especially in the case of repeated coughing) 
should give cause for it. 

6. That the animals should be exactly numbered (first by earmarks, later by ])rand- 
ing the number on one horn) and entered in books. 

7. That animals from other stocks, no matter how young, should only be admitted 
into the protected establishment from stocks free from reaction, or, in case that this 
presents insurmountable difficulties, from other stocks only with certain precautions. 

According- to Regner's observations a single incautious purchase for 
a herd free from reaction may in a short time bring to naught the 
the result of a year's or of many years' work devoted to rooting out 
tuberculosis in that herd. The condition generall}" made that the pur- 
chased animal should be free from reaction is not sufficient in itself. 
Should the purchased animal come direct from a stock well known to 
be free from reaction, and which has been for years subject to pro- 
tective precautions, and should the animal have been born and reared 
in that stock, then all is well. In any other case the purchaser must 
demand such information as to the stock from which the purchase is 
to be made as may clearl}^ show the prevalence of tuberculosis. The 
stock must therefore be tested and the result laid before the pur- 
chaser. Should the farmer decide to purchase from an infected herd 
animals free from reaction, and which have also been tested clinically 
with negative resiilts, he would do well to disinfect the animal after' 
its arrival at his farm, above all with regard to the hoofs and the lower 
part of the legs, and if possible keep it half a year in quarantine. 
Should local conditions not admit of this, the animal should be placed 
in a stall apart from the others and nmst not be removed from its 
place until it has underg'one a new testing with a double quantity 
of tuberculin, which in any case must be made after the interval 
mentioned. 

Immunization in Connection with the Banc; Method. 

It appears probable from the results which have been published of 
recent researches, the more important of which have been summarized 
above, that the immunization of bovine animals will be of great assist- 
ance in freeing a herd from disease when practiced in connection with 
the Bang- method. In this case the 3^oung cattle which do not react to 
the tuberculin test, and all of the calves when a week old, would be g'iven 
an immunizing injection and removed to a stable free from infection. 
If the method selected requires that two doses should be g'iven, the 
second dose should be administered to the animals in the uninfected 
stable after a proper interval of time has elapsed. As several months 



88 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

are required for the development of the immunity after the vaccine is 
injected, it i« essential that there should be complete isolation from 
infected cattle during this period, as required by the Bang method. 

It appears that calves may be very successfully immunized, but it 
is not certain that this is true of grown cattle, and therefore the 
tuberculin test and isolation must be relied upon with the adult ani- 
mals. The duration of the immunity is yet uncertain, and for this 
reason it is difficult to estimate the degree of assistance which will be 
rendered Ijy immunization. 

The immunization of cows, assuming that investigations show that 
this may be successfulh^ accomplished, would raise the question as to 
the danger which this method might cause to the consumer of the 
milk. The immunizing material is the human tubercle bacillus which 
has not been deprived of all its dangerous qualities, and when this is 
injected into the blood it causes an elevation of temperature and per- 
haps other signs of illness. Is there danger of this bacillus contami- 
nating the milk during the period that it is circulating in the blood of 
the animal^ And, further, does the illness caused by the immunizing 
dose of the vaccine have any injurious effect upon the composition of 
the milk which might render this liquid injurious to the consumer? 
These are questions of a serious nature, and they should receive a 
scientific answer before the immunization of milk-producing cows is 
practiced. 

Assuming, for the moment, that the imnninization of milch cows is 
practicable and proper, it would follow that all nonreacting animals 
should receive an immunizing injection when they are placed in the 
isolated stable. This should guard against the continued appearance of 
the disease in the healthy section of the herd, as has been so frequently 
the case where perfect isolation could not be maintained. 

It is not probable, however, that isolation of the healthy animals 
can be altogether dispensed with. The long period which is required 
for the development of the immunity would make the chance of infec- 
tion far too great if the nonreacting vaccinated animals remained in 
the same stable with those which were diseased. If, however, the 
vaccination were conducted during the season of pasturage, and the 
animals sta])led only during milking, and particularly if but a small 
proportion of the herd reacted, it seems probable that the isolation 
might be omitted without serious consequences. 

Experience with innnunization is, as yet, so limited, and so many of 
the accounts published appear to be biased by commercial considera- 
tions, that it is too soon to predict definitely the extent of its useful- 
ness as a practical measure for the control of tuberculosis. If it aids 
in any degree in eradicating this disease, or in lessening the burden 
which falls upon the owners of diseased herds, it will be a most welcome 
addition to our resources. 



THE REPRESSION OF TUBERCULOSIS. 89 

Destruction of Reacting Animals and Creation op a Sound Herd. 

The objectiou to the Bang system and to all moditieations of it is the 
length of time that tiiberciiloiis animals must be kept on the premises, 
injuring the reputation of the herd and causing much extra work in 
caring for two herds, sterilizing milk, and taking precautions to pre- 
vent infection of the health}' animals. It is true that the prescribed 
precautions are not always carried out. and equally true that in such 
cases there is usually not yery marked success in getting rid of the 
disease. For this reason it has been considered best, where the cattle 
haye no special yalue for breeding purposes, to slaughter reacting ani- 
mals, and disinfect the stable and thus immediately to stamp out the 
disease. Most dairymen prefer this plan as the more economical of 
the two. 

The eradication of tuberculosis from the herd of the jVIaine Agri- 
cultural College" is a valuable example of what may be done by this 
plan. 

Since some years before 1886 until within two years, wlienever the college has kept 
any cattle on the college farm some of them have been affected with tuberculosis. 
Before 1886 cattle occasionally died from this disease or, in absence of exact knowl- 
edge of their condition, were sold for beef or otherwise disposed of on account of age 
or unthriftiness. Well-bred young animals were sold to improve other herds and 
sometimes carried tuberculosis with them. 

In 1886 the cattle were so badly diseased that it was considered best to kill the 
entire herd. After the herd was destroyed the barns were disinfected with some 
care and no new stock was introduced for about a year. In 1889 consideraVjle new 
stock was purchased from different sources, and in less than a year from the time 
they were purchased two of the animals were found to be diseased and were killed. 
Again the barn was disinfected, but new cases of disease were frequently being dis- 
covered in the herd. 

In 1892 tuberculin became available for the detection of tuberculosis, and experi- 
ments were soon made at the college to test its value. 

By 1893, having become convinced of the value of tuberculin, every bovine animal 
on the farm down to the youngest calf was tested, and those that reacted to the test 
were killed. This made a large hole in the herd and required the sacrifice of some 
of the most valued animals, but it is believed the results have fully justified the 
course taken. 

In order to meet the demands for dairy products it was considered necessary to 
replace the cows killed, and ordinary grade and native cows that answered the 
requirements were purchased from near-by sources. Every j^recaution was taken to 
procure sound animals, and before they were introduced into the barns they success- 
fully passed the tuberculin test, but as it was late in the fall and the barn was full of 
hay and grain it was not considered practicable to disinfect the barn. The lintel was 
disinfected, but not the rest of the barn until the following summer. 

During the winter of 1893-94 and the following spring several cases of tuberculosis 
developed, some of them l)eing cows purchased the fall before from healthy herds, 
and, according to every known test, healthy animals themselves. They must have 
contracted the disease in the college barns. In the summer of 1894 the barn was 
disinfected, and since that time comparatively few cases of tuberculosis have been 
found, the last case being discovered in the fall of 1897. In 1896, the barn was again 
disinfected in a very thorough manner. Since then but two cases have been found, 
and both of them were discovered before it was possible that they should have 
infected their surroundings or other cattle. Since October, 1897, no new case has 
been discovered, although the entire herd was tested in 1897 and again in 1898. It 
is believed that since October, 1897, the herd has been entirely free from tuberculosis 
for perhaps the first time in its history. The herd now numbers 51 head of all ages, 
most of these bred on the farm. 

The method of disinfection by which the barn was freed from the contagion is of 
much interest: 

All the hay, grain, and farming tools were removed from the barns, the only 
exception being the hoes, shovels, and forks that had to be used there. Every mov- 



90 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

able thing that had been in the barn witli the diseased cattle, or after the diseased 
cattle were removed, before the barn was disinfected, was taken ont, or, if left in the 
barn, was disinfected in the same manner as the l)arn itself. Then with brooms all 
dust and dirt that could be moved was swept into the basement or out of doors into 
the sunlight. Then with a hand pump mounted on a barrel, such a pump as is com- 
monly used in spraying orchards or potalo lields, the disinfecting solution was thrown 
with considerable force against ever\' inch of the woodwork of the barn, into every crack 
and crevice where dust, laden with disease germs, might lodge. The workmen com- 
menced in the roof and worked downward, making thorough work of it as they went 
along. By using tlie pump this was not a very expensive operation. Including the 
cost of the material and lal^or, the expense of cleaning and disinfecting a barn 50 
by 100 feet with IS-foot posts and basement was about $25. This did not include the 
cost of the pump, which was but little injured, and had before and has since that 
time been used for other purposes. The disinfecting solution was made by dissolv- 
ing 1 part, by weight, of corrosive sublimate in about 1,000 parts of water. The 
pump was mounted on a 50-gallon barrel and a little more than j- pound of the sub- 
limate was used for a barrel of water. The pulverized corrosive sublimate was pur- 
chased and this was dissolved in hot water, as it dissolves very slowly in cold water. 
The sublimate and its solution should be kept in glass or wooden vessels; it corrodes 
metal. The solution is poisonous if taken in sutticient quantities, so it should never 
be left uncovered where animals can get at it. 

Another means that has been used in keeping this herd free from tuberculosis has 
been the testing witJi tuberculin of all animals purchased. By this means the pur- 
chase of diseased animals that were satisfactory in other respects has been avoided. 
When convenient the animals purchased were tested before they were brought to 
the farm. In other cases they were tested on the college farm before they were 
admitted to the barns with the other cattle. In two cases the introduction of tuber- 
culous cattle into the herd was avoided by this very simple precaution. 

A thorouo-h disinfection is necessaiy, and ttiis shotild be practiced 
immediately after the diseased animals are removed from the stable. 
Russell and Hastings^* say that it is manifestly useless to eradicate 
this disease from a herd unless at the same time the infected quarters 
are subject to a thorough disinfection. One case that came to their 
attention sufficiently illustrates this point. Within the past two years 
a herd of cows was tested and the larger part of the herd condemned 
by the test and slaughtered. A post-mortem examination showed 
many of them to be badly diseased. A short time afterwards a new 
herd was purchased and introduced into the same quarters. In less 
than a year it was found that many of this second herd had also acquired 
this same disease. Undoubtedly they contracted the same from the 
infected quarters in which they were placed. 

In order to carry out such a disinfection there should be first a 
thorough cleaning with brooms to remove all litter and dust, not only 
from the floor, but from the walls, the roof, and all projections where 
dust may lodge. All loose boards and decayed woodwork should be 
removed. The floor of the stable should l)e washed with water and 
the mangers and stalls with a hot solution of Ij^e. The whole interior 
of the stable should then be sprayed with the disinfecting solution. 
Every crack and crevice should be filled with disinfectant and every 
part of the walls should be covered. There are many different kinds 
of spra}' pumps which are available for this purpose. 

Poisonous disinfectants or those having a strong and lasting odor 
should, if possible, be avoided. A thin lime wash made from freshly 
burned lime is the most satisfactory disinfectant to use about a stable. 



THE REPKESSION OF TUBERCULOSIS. 91 

Its activity ina}^ be increased by the addition of 4 ounces of formalin 
to 1 gallon of lime wash. Corrosive sublimate and carbolic acid are 
often recommended for this purpose, but as both are dangerous poi- 
sons, and as the latter has an objectionable and persistent odor, it is 
deemed best to use lime wash and formalin, which probabl}' are just as 
effective in destroying the tubercle bacillus. 

In adding new animals to the herd they should be tested with tuber- 
culin before purchasing, and then, if possible, they should be kept in a 
separate stable for six months and afterwards tested a second time 
before the}^ are placed with the healthy cattle. This precaution will 
usually be sufficient to prevent the reinfection of the herd by the pur- 
chased animals. It should be remembered, however, that some of the 
animals of the herd which did not react may nevertheless have been 
infected, and to detect any cases of this kind there should be a second 
test made of the entire herd in about six months. If any reactions 
occur, the reacting animals should be removed and the stable disin- 
fected as before. The herd should be tested at least once a 3^ear for 
two or three 3^ears after the last reaction has occurred. 

With hogs the eradication of tuberculosis from a badly infected 
herd is a difficult matter. The best course to pursue is probably to 
destroy the entire herd, thoroughly disinfect the pens, and after a few 
months to start with a new herd known to be free from disease. A 
boar may be retained from the old herd, if considered very desirable, 
but it should be kept isolated from the new herd except during service. 
For the same reason it is well to keep newly purchased boars similarly 
isolated. This simple precaution may often prevent the infection of 
a herd. The increasing prevalence of tuberculosis in swine empha- 
sizes the importance of precautionary measures being adopted by the 
breeders of these animals. 

STATE AID FOR THE ERADICATION OF TUBERCULOSIS. 

In the eradication of a disease so widely disseminated, and one which 
causes such serious losses to the animal industry of the country, there 
should be assistance offered by the State in order to relieve the Inir- 
dens which fall upon the owners of live stock. A considerable num- 
ber of States have shown a disposition to come to the assistance of 
farmers whose stock is affected, but the assistance has sometimes been 
coupled with conditions which made it unwelcome. In some States 
compulsor}" testing and the slaughter of reacting animals have been 
required, but this has not been a popular measure. It is essential that 
a plan should be devised which will meet with the approval of the 
stock owners and which will aid them without being too burdensome 
in its conditions. There are certain measures which have been adopted 
by individual States which have accomplished satisfactory results, but 
which would be far more successful if adjoining States would adopt 
the same or similar reefulations. Among the reasonable measures 



92 TUBEECULOSIS OF THE FOOD-PRODUCING ANIMALS. 

which a State may adopt for the repression of tuberculosis the follow- 
ing may be mentioned: 

1. Cattle which are liroiight into a State for breeding or dairy pur- 
poses may be tested with tuberculin, and those which react may be 
refused admission to the State. In connection with this measure it 
should be provided that cattle which have been tested by the authori- 
ties of another State or of the Federal Government and found free 
from disease should l)e allowed admission without being retested. 
The testing of animals coming into a State is essential in any effort to 
control this disease, and is one of the lirst measures which should be 
enforced in an}" effort to eradicate it. 

2. There should be an inspection of all slaughtered animals coming 
from breeding or dairy herds within the State in order to discover in 
what herds the disease exists. Animals from the greater part of the 
milk-producing herds are being continually sold for slaughter as their 
usefulness in the dairy is over, and an examination of the carcasses of 
these cows would serve to locate the existence of the disease in many 
hei-ds where its presence is unsuspected. Unfortunately few of the 
animals killed in the small slaughterhouses are inspected, and in those 
cases where there is an inspection and tuberculosis is discovered it is 
seldom that the herds from which they came are traced and the own- 
ers informed of the discover}- of this disease. In any effort to sup- 
press tuberculosis it is almost essential that information of this kind 
should be obtained and an attempt made to persuade the owner to 
adopt proper measures for getting rid of the contagion. 

3. Measures should be adopted for testing herds with tuberculin 
without expense to the owners. In the beginning of the work, at 
least, this should not be compulsory, but it should be made to the 
interest of the owner of a tuberculous herd to have it tested under 
the auspices of the State. Apparently it would also be wise and a 
great aid to stockmen for the State to test herds with tuberculin and 
certify to the healthf ulness of animals from all those herds where no 
reactions occur. At present it is a difficult matter in most States for 
the breeder or dairyman to purchase cattle for his herd with any 
assurance that they are healthy. He may have them tested, but there 
is always a possi))ility that they have been treated with tul)erculin a 
short time before and that for this reason they have not reacted. The 
loss which has fallen upon the breeders of the country through the 
introduction of tuberculosis in their herds has been tremendous, and 
it appears that it would be only a proper aid and encouragement to 
agricultural interests to assist breeders in obtaining animals free from 
disease. Not only would this encourage farmers to enter into breed- 
ing operations and increase the value of the industry within the State, 
but the certification of breeding animals would help to build up a 
market in other States for breeding animals. 



THE EEPEESSIOJSr OF TUBERCULOSIS. 93 

4. In order to encourage the owners of cuttle to eradicate tuber- 
culosis, States should allow a reasonable compensation for the animals 
which it is necessary to slaughter on account of being affected with 
this disease. It is certainl}^ a matter of great importance to any State 
to have its herds free from tuberculosis and its animals and animal 
products above suspicion. With the recent demonstration of the 
comnmnicability of animal tuberculosis to man, a demonstration 
which has been made by so man}^ investigators and on such competent 
authority that the fact can no longer be questioned, there is a disposi- 
tion on the part of sanitary authorities to scrutinize more carefully 
those animal products which are liable to be infected. It is, there- 
fore, becoming ever}^ day more important for ever}^ State to repress 
tuberculosis within its borders and in that manner to maintain the 
reputation of its animal products. Where it is not deemed advisable 
to provide for slaughtering of all reacting animals with sufficient com- 
pensation from the State to make this measure satisfactory to the 
stockmen, the State may provide for the supervision of herds handled 
according to the Bang method or some modification of it. For the 
protection of its own citizens who consume dair}' products, if not for 
the protection of its customers in other States, every State should 
make some arrangement which would lead to the removal of cows with 
tuberculous udders, and those suffering from generalized tuberculosis, 
from herds which suppl}^ milk, cream, and butter for human food. 
This much is essential for the public health, but it would be wise to 
go further and provide for the slaughter of all cows which show evi- 
dence on ph3'sical examination of being affected with tuberculosis. 

5. In cases where cattle owners are to have their tuberculous animals 
slaughtered in an effort to free their herds from disease the State 
should further assist them by disinfecting or at least supervising the 
disinfection of the contaminated stables. It is a somewhat difficult 
matter for persons not acquainted with the practical operations of dis- 
infection to carry out this measure successfully, even after they have 
been given explicit instructions. It is impossible to impress suffi- 
ciently the importance of thoroughness upon persons who are lacking 
in experience in this line of work. As a consequence the majority 
of the premises disinfected by stockmen without the assistance of 
experts are imperfectly disinfected, and the disease breaks out again 
among the animals which are subsequentl}^ introduced. This is dis- 
couraging to the owner and serves to fix the impression that it is 
impossible to eradicate tuberculosis. This impression is already wide- 
spread, but it is essentially wrong, though it can onl}' be removed by 
object lessons in the eradication of the disease under State super- 
vision. There is no reason why tuberculosis should not be eradicated 
as pleuro-pneumonia was eradicated. The contagion is more wide- 
spread and the expense would be greater, but there are no inherent 
difficulties to prevent the success of such an undertaking. 



9-4 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

0. When a herd has been freed from tuberculosis l)y the slaughter 
of all reacting- animals, and the premises have been properly disin- 
fected, the State should give further aid to the stock owner by testing 
without expense the animals which he desires to purchase for renew- 
ing his herd. This measure is essential to the success of any plan for 
lessening the prevalence of this disease or eradicating it. The expense 
of testing such animals is almost too great to l)e borne by the individ- 
ual, and, moreover, private tests are often unsatisfactory and unreliable. 

FEDERAL COOPERATION FOR THE ERADICATION OF 
TUBERCULOSIS. 

The aid of the Federal Government is essential to the success of any 
efl'orts for the eradication of tuberculosis. The disease ma}' be held 
in check by the exercise of the authority of the individual States, but 
the action of the States has been too spasmodic and not sufficient!}^ 
general and harmonious to have much effect upon the prevalence of 
the disease in the country at large. There is needed a systematic plan 
of repression which shall be generally applied. 

At no time has there been more public interest manifested in meas- 
ures for reducing the mortality from tuberculosis in human beings 
than the present. Societies for furthering such measures are being 
formed in every part of the land and a propaganda of education is 
being conducted on a magnificent scale. It has already been shown 
that human tuberculosis and animal tuberculosis are communicable 
between persons and animals, and that a not inconsiderable proportion 
of the cases of human tuberculosis, and especially of the tuberculosis of 
children, is caused liy infection from animal sources. It is important 
to the success of the etforts against human tuberculosis, therefore, that 
the continuous infection of human subjects by contagion from the 
lower animals should be prevented. The present is, consequently, an 
opportune time for the Federal Government to extend its aid to those 
States w hich are willing to cooperate for this purpose. Not only would 
such action be an aid to agriculture, but it would at the same time 
serve as a protection to human life. 

The lines of work which the Federal Government might undertake 
may be formulated as follows: 

1. Infected herds of cattle and swine could be readily located through 
the meat-inspection system and through the tuberculin tests that might 
be required for cattle that are to be shipped from State to State or to 
foreign countries. The meat-inspection service offers a magnificent 
opportunity for the discovery of affected herds by tracing the diseased 
animals, which are discovered daily, back to the farms upon which 
they were raised. There are probably but a small proportion of the 
shippers of tubercular hogs who know that they have this disease in 
their herds, and the evidence of the fact, which is discovered in the 



THE REPRESSION OF TUBERCULOSIS. 95 

abattoirs, is never brought to their attention. It is also true, as is 
proved b}^ examples already given in these pages, that a herd of cattle 
may be affected for a long time and a large proportion of its members 
be diseased before the owner becomes aware of the existence of tuber- 
culosis. A systematic effort on the part of the Government to dis- 
cover the disease, followed by the communication of the information 
both to the owner and to the proper State authority, would prove of 
great value in furthering this work. 

2, The Government might also \ery properly test with tuberculin 
breeding animals intended for interstate shipment upon the request 
of the owners and under suitable conditions. Bj^ doing this it would 
be preventing the interstate shipment of diseased animals, and at the 
same time adding greatly to its resources for discovering infected 
herds. 

It would be a most important step to test breeding herds and certify 
to the healthfidness of animals from those which proved to l)e free 
from disease. There must be a large proportion of American herds 
which are not affected with tuberculosis. In Denmark, where 50 per 
cent of the cattle were affected, 22 per cent of the herds were entirely 
free from the disease. In the United States, with less than 5 per cent 
of the cattle infected, there should be at least 80 per cent of the herds 
in a health}^ condition. This being the case, it would be of great 
importance to the owners of the vast majority of herds to have an 
inspection and to receive certificates showing the healthfulness of their 
animals. On the other hand, there could be no greater inducement to 
the owner of a diseased herd to put it into healthful condition than 
the fact that his herd was not registered as f i"ee fi'om disease and that 
he could not obtain certificates as to the health of his stock. 

3. It is doubtful if it would be advisable to cooperate with State 
authorities with a view to the compulsory slaughter of tuberculous 
animals. This work has succeeded better where the owner has volun- 
tarily participated in eradicating the disease; and it appears impor- 
tant that he should be interested financially in accomplishing this 
object. The Government may stimulate this interest by testing his 
cattle without expense and by giving him expert advice as to the 
measures to be used in eradicating the disease. It may also ag-ree to 
compensate him liberally for an}' animals which are found diseased 
and which it ma}^ be necessary to slaughter. But it proliably should 
not cooperate with the States on the lines which were followed with 
plcuro-pneumonia and foot-and-mouth disease with a view to compel 
him to accept its terms. In some of our States and in several Euro- 
pean countries the repression of tuberculosis is being conducted with 
considerable success by measures which ai'e voluntarily accepted b}^ 
the owners and which secure their cooperation not only in getting rid 
of the disease, but in guarding against a reinfection of the herd. 



96 TUBERCULOSIS OF THE FOOD-PRODUCING ANIMALS. 

A departure from old methods, and one which promises valuable 
results, has been made by the Swedish Government, which, since 
November 1, 1903, has been engaged in forming ])roeding- centers for 
cattle, one of its objects being to promote the industry by breeding 
animals free from tuberculosis. The formation of breeding centers 
for improving the live stock of certain sections of the country has 
alread}^ been discussed in the United States, and such a movement 
might well receive the encouragement of the Government and include 
within its sphere the development of herds free from tul^erculosis. 

Any or all of the measures enumerated are worthy of consideration 
in this connection. The prosperity of the live-stock industr}" in the 
United States will depend, for years to come, upon foreign markets 
for animal products. If we can compete in those markets in price, in 
quality, and in reputation for healthfulness, we shall continue to sell 
our meats; otherwise we shall lose the trade. It is not an age when 
markets can be held without striving for them; competition is tierce, 
and already our bacon and dressed beef trades seem to be yielding to 
the attacks of our competitors. Tuberculosis in our herds increases 
the cost of producing meat, and if other countries outstrip us in prac- 
tical work for its eradication, as se6ms probable from efforts now in 
progress, that fact will be used to our disadvantage. 

Fortunately the percentage of tuberculosis in our herds is still rela- 
tively low, and the conditions under wdiich live stock is raised in this 
country are favorable for the eradication of disease. When public 
sentiment favors the eradication of tuberculosis in animals the task 
will not be found an iuj possible one. 



BIBLIOGRAPHY 



1. Russell, H. L., and Hastin(;s, E. G. Bovine tuberculosis in Wisconsin. Wis- 

consin Agr. Exp. Sta., Bull. 84. Madison, Wis., March, 1901. 

2. Pearson, Leonard, and Ravenel, Mazyck Porcher. Tuberculosis of cattle and 

the Pennsylvania plan for its repression. Pennsylvania Department of Asjri- 
culture. Bull. 75. [Harrisburg], Pa., 1901. 
:>. Russell, H. L. Two ways of treating tuberculosis in herds. Wisconsin Agr. 
Exp. Sta., Bull. 126. Madison, Wis., June, 1905. 

4. Report to legislature of majority of commissioners for Maine on contagious 

diseases of animals. 1887. 

5. U. S. Department of Agriculture, Bureau of Animal Industry. Bull. 7. 

Investigations concerning bovine tuberculosis. Wash., 1894. 

6. MoHLER, John Rokbins. Infectiveness ot milk of cows which have reacted 

to the tuberculin test. U. S. Department of Agriculture, Bureau of Animal 
Industry, Bull. 44. Wash., 1903. 

7. Paige, James B. Tuberculosis and tuberculin at the Massachusetts agricultural 

college. Hatch Agr. Exp. Sta., Bull. 27. Amherst, Mass., December, 1894. 

8. Nelson, Julius. Report of the biologist on the use of Koch's lyin{)h in the 

diagnosis of tuberculosis in cattle. Report of the biol. dept. of the New Jersey 
Agr. Coll. Exp. Sta., for year 1893. Trenton, N. J., 1894. 

9. Fischer, Paul. Bovine tuberculosis. Kansas Agr. Exp. Sta., Bull. 79. [Man- 

hattan], Kans., April, 1898. 

10. Russell, H. L. Tuberculosis and the tuberculin test. Wisconsin Agr. Exp. Sta., 

Bull. 40. Madison, Wis., July, 1894. 

11. Beach, G. L. The history of a tuberculous herd of cows. Storrs Agr. Exp. Sta., 

B ill. 24. Storrs, Conn., November, 1902. 

12. BuFFUM, B. C. Tulierculin tests of the college herd. Colorado Agr. Exp. Sta., 

Bull. 66. Fort Collins, Colo., 1901. 
1.3. Thornk, Charles E. Bovine tuberculosis. Ohio Agr. Exp. Sta., Bull. 108. 
Columbus, Ohio, June, 1899. 

14. Stubbs, VVm. C, Staples, S. B., and Dalrymplk, W. H. Bovine tuberculosis in 

North Louisiana. La. Agr. Exp. Sta., Bull. 43, second series. Baton Rouge, 
La., 1896. 

15. Lamson, Herbert H. Bovine tuberculosis. New Hampshire Agr. Exp. Sta., 

Bull. 78. Durham, N. H., October, 1900. 

16. Hall, F. H. In the station dairy; mottles in butter; health in the herd. 

Country gentleman, v. 71, no. 2762. Albany, N. Y., Jan. 4, 19C6. 

17. Brewer, F. W. Tuberculosis. Utah Agr. E.xp. Sta., Bull. 41. Logan, Utah, 

1895. 

18. Scott, John M. Tuberculosis in cattle and tuberculin tests of the station herd. 

New Mexico Agr. Exp. Sta., Bull. 55. Santa Fe, N. Mex., June, 1905. 

19. Saunders, \Vm., and Robertson, James W. Tuberculosis. Canada Department 

of Airriculture, Central Experimental Farm, Ottawa, Bull. 20. Ottawa, Feb- 
ruary, 1894. 

20. Ostertag, Robert. Handbuch der fleischbeschau. Berl., 1904. 

21. Regner, GusTAV. Bekiimpfung der tuberkulose der haustiere. Read at Eighth 

international veterinary congress, Budapest, 1905. 

22. BAN(i, B. Report read at P^ighth international veterinary congress, Budapest, 

1905. 

23. See Citation 5. 

24. Phelps, C. S. Results of experiments with tuberculous cows, and the use of 

their milk in feeding calves. Storrs Agr. Exp. Sta., Bull. 23, pp. 9-20. Storrs, 
Conn., April, 1902. 

25. Ru.ssELL. H. L. A lesson in bovine tuberculosis. Wisconsin Agr. Exp. Sta., 

Bull. 114. Madison, Wis., June, 1904. 

1881— No. 38—06 7 97 



98 TCIBPZRCULOSIS OF THE FOOD-PRODUUING ANIMALS. 

26. See Citation 1 1 . 

27. Ban(4, JB. Daniier.^ (In lait tuberculeux. Ci)mptef^ rendu.-^ et memoires, Conjjres 

pour I'etude de la tuberculose chez rhomnie et chez les aniinanx. rreniiere 
session, ]888. p. 69-72. Paris, 1889. 

28. Banc, B. Le danger suppose de la eonsommatiou du lait et de la viande sains 

en apparence mais provenant d'animaux atteints de. la tnberculose. Trans, of 
Seventh international congress of hygiene and denioi;rapiiv, London, August 
10-17, 1S91. V. 2, seetion 2, Bacteriology, p. 19.3-197. Lond., 1892. Cited in 
U. S. Department of Agriculture, Bureau of Animal Industry, Bull. 44. See 
Citation ti. 

29. Rabinowitsch, Lydia. Ueberdie gefahr der uebertragung der tuberknlose durch 

milch und milchprodukte. Dent. med. woch., jlig. 26, no. 26, pp. 416-418. 
Berl., June 28, 1900. 

00. Adami, John Georc^e. On the significance of bovine tuberculosis and its eradi- 

cation and prevention in Canada. Phila. med. jrn., v. 4, no. 26, p. 1277-1284. 
Phila., Deceml)er30, 1899. 

01. Gehrmaxn, Adolph, and Evans, W. A. Tuberculosis and the tuberculin test. 

State board of live stock commissioners of Illinois, Bull. 1, series of 1900. 
Springfield, 111., March 29, 1900. 
.■^2. See Citation 6. 

33. BoNGERT, J. Ueber die art der infektion bei der tuberknlose der haustiere. Read 

at Eighth international veterinary congress, Budapest, 1905. 

34. See Citation 1. 

35. ScHROEDER, ErxstC, Hud CoTToN, W. E. Spread of tuberculosis among healthy 

cattle upon exposure to tuberculous cattle. U. S. Department of Agriculture, 
Bureau of Animal Industry. Twentieth annual report for the year 1903. 
p. 61-68. Wash., 1904. 

36. OsTERTAG, Robert; Breidert, Kaesewurm, and Krautstrunk. Untersuchungen 

liber die eutertuberkulose und die bedeutung der sogenannten siiurefesten 
psendotuberkelbazillen fiir die feststellung der eutertuberkulose. Ztschr. f. 
tleisch- u. milchhyg., jhg. 15, hft. 1, p. 1-10. Berl., October, 19li4. Transl. of 
above in Jrn. of comp. path, and ther.. v. 18, pt. 1, p. 84-86. Edinb. and 
Lond., March, 1905. 

37. VoGES, O. Der kampfgegen die tuberknlose des rindviehs. 82 p. 26 cm. Jena, 

1897. See p. 14-15. 

38. Eber, a. Feststellung einheitlicher grundsiitze fiir die beurteilung der tul)erku- 

lin-reaction beini rinde. Read at Eighth international veterinary congress, 
Budapest, 1905. 

39. Salmon, Daniel Elmer. The tuberculin test for tuberculosis. U. S. Dei^artment 

of Agriculture, Yearbook for 1901, p. 581-592. Wash., 1902. 

40. Pearson, Leonard. The repression of tul)erculosis of cattle by sanitation. 

Pemisylvania Department of Agriculture, Bull. 74. [Ilarrisburg], Pa., 1901. 

41. Daremberg. De revolution variable de la tnberculose experimentale. Bull, de 

I'acad. de med., Paris, sen 3, t. 22, p. 391-404. Paris, 1889. 

42. Ctrancher, and Martin, H. Tnberculose experimentale. Bull, med., ami. 4, 

p. 777. Paris, 1890. 

43. Triideau, E. L. An experimental study of preventive inoculation in tuberculosis. 

Med. rec, v. 38, no. 21, p. 565-566. N. Y., November 22, 1890. 

44. Tkudeau, E. L. Report of the ultimate results obtained in experimental eye 

tuberculosis by tuberculin treatment and antitubercular inoculation. Trans, 
assn. Am.phys., ninth session, v. 9, p. 168-173. Phila., 1894. 

45. Schweinitz, Emil Alexander de. The attenuated bacillus tuberculosis; its use 

in producing immunity to tuberculosis in guinea piss. Med. news, v. 65, no. 
23, p. 625-629. N. Y., December 8, 1894. 

46. Schweinitz, E.mil Alexander de, and Schroeder, Ernst C. Further experi- 

ments with an attenuated tuberculosis bacillus. U. S. Department of Agricul- 
ture, Bureau of Animal Industry, Bull. 13, Tuberculosis Investigations, p. 11-14. 
Wash., September 19, 1896. 

47. Salmon, Daniel Elmer. Inmuniization from tuberculosis. Phila. med. jrn., 

y. 11, no. 24, p. 966-970. Phila., June 13, 1903. 

4S. McFadyean, J. Ex]>eriments regarding the immunization of cattle against tuber- 
culosis. Jrn. comp. path, and ther., v. 14, pt. 2, p. 136. Fldinb. and Lond., 
June, 1901. 

49. McFadyean, J. Further experiments regarding the immunization of cattleagainst 
tuberculosis. Jrn. comp. path, and ther., v. 15, pt. 1, p. 60-71. Edinb. and 
Lond., March, 1902. 



BIBLIOGRAPHY. 99 

50. Pearson, Leijnard, and Gillilaxd, S. H. Some experiments ui:)on the immu- 

nization of cattle against tnl)ei'fulosis. Jrn. comp. med. and vet. arch., v. 23, 
no. 11, p. 673-688. "Phila., Novemlier, 1902. 

51. Behring, Emile von, Romer, Paul, and Ruppel, W. (t. Tuberkulose. Beit. z. 

exp. ther., lift. 5-8. Berl., l!)02-iy04. 

52. Vallee and Pani.sset. Contril)ution to Presse veterinaire, April, 1905, cited by 

Basset. See Citation 60. 

53. Eber, a. Ueber die widerstandsfiihigkeit zweier in Marljuro; mit tnberkel- 

bazillen verschiedener herkunft vorbehandelter rinder gegen subkutane und 
intravenose infektion mit tuberkulosen, von rinde stammenden virus. Berl. 
thienirztl. wocli., no. 53, p. 888-891. Berl., December 29, 1904. Trans, abst. 
of al)ove in Jrn. comp. path, and ther., v. 18, pt. 1, p. 86-88. Edinb. and 
Lond., March, 1905. 

54. HuTYRA, Franz. Schutzimpfungsversuche gegen die tuberkulose der rinder 

nach von Behring's methode. Beit. z. exp. ther., hft. 9, p. 1-17. Berl., 1905. 

55. HuTYRA. Franz. Schutzimpfung gegen die tuberkulose der rinder. Read at 

Eighth international veterinary congress, Budapest, 1905. 

56. Thomassen. L' immunisation des jeunes bovidescontre la tuberculose. Reed. 

med. vet., t. 80, no. 1, p. 5-19. Paris, January 15, 1903. 

57. Thomassen. Vaccination contre la tuberculose. Read at Eighth international 

veterinary congress, Budapest, 19: 5. 

58. Klimmer, M. Bericht iiber die im hygieni,^chen institut der koniglich tieriirzt- 

lichen hochschule ausgefiihrten tul)erkulose-arbeiten. Berl. tienirztl. woch., 
no. 37, p. 465-469. Berl., July 5, 1905. 

59. Koch, Robert, Schutz, W., Neufeld, F., and Miessner, H. Ueber die immuni- 

sierung von rindern gegen tuberkulo.se. Arch. f. wiss. u. prakt. thierheilk., 
bd. 31~hft. 6, p. 545-575. Berl., August 5, 1905. 

60. Bassett, J. Compte rendu de I'experience de vaccination antitubereuleuse de 

Melun. Rec. d. med vet., t. 82, no. 23, p. 815-819. Paris, L)ecend)er 15, 1905. 

61. KossEL, H. and Weber, H. Wissenschaftliche ergebnisse der bisl^r im kais. 

gesundheitsamt angestellten vergleichenden untersuchungen liber tuberkel- 
bazillen verschiedener herkunft. Ztschr. f. tuberkulose u. heilstJittenwesen, 
bd. 7, hft. 6, p. 548-549. Leipz., October, 1905. 

62. Praktische ergebnisse der neueren forschungen fiber die beziehungen zwischen 

der menschen- und tiertul^erkulose. Festgestellt in der sitzung des unteraus- 
schussesfiir tuberkulose des reichs-gesundheitsrates vom 7. Juni 1905. Ztsch. 
f. tuberkulose u. heilstiittenwesen, bd. 7, hft. 6, p. 546-547. Leipz., October, 
1905. 

63. Pearson, Leonard, and Gilliland, S. H. The effect of tuberculosis vaccina- 

tion upon cattle infected with tuberculosis. Univ. of Penn. med. bull., v. 18, 
no. 12, p. 30-35. Phila., April, 1905. 

64. Bang, B. Tuberculosis of cattle. Pennsylvania Department of Agriculture, Thii'd 

annual report, for 1897, pt. 1, p. 480-494. [Harrisburg], 1896. 

65. U.iHELYi, E. Bekiimpfung der tuberkulose der haustiere. Read at Eighth intei'- 

national veterinary congress, Budapest, 1905. 

66. Russell, H. L. The history of a tul)erculous herd of cows. Wisconsin Agr. 

Exp. Sta., Bull. 78. Madison, Wis., August, 1899. 

67. Russell, H. L. Tuberculosis and the station herd. Maine Agr. Exp. Sta., 

Fourteenth annual report, for 1898, p. 136-149. Augusta, Me., 1899. 



o 



